Techniques for managing a plurality of radio access technologies accessing a shared radio frequency spectrum band

ABSTRACT

Techniques are described for wireless communication. A first method includes sensing an indication of first radio access technology (RAT) communications occupying a shared radio frequency spectrum band; and configuring, in response to the sensing, at least one parameter of a second RAT used by a device to contend for access to the band. A second method includes randomly selecting a number from a range of numbers extending between a lower bound and an upper bound; contending for access to a shared radio frequency spectrum band by performing an extended clear channel assessment (ECCA) procedure over a plurality of CCA slots, the plurality of CCA slots including a first number of CCA slots equal to the upper bound; and winning contention for access to the band after determining, while performing the ECCA procedure, that the band is available for a second number of CCA slots equal to the randomly selected number.

CROSS REFERENCES

The present application for patent is a Continuation of U.S. patentapplication Ser. No. 15/913,739 by Yerramalli et al., entitled“Techniques for Managing a Plurality of Radio Access TechnologiesAccessing a Shared Radio Frequency Spectrum Band” filed Mar. 6, 2018,which is a Continuation of U.S. patent application Ser. No. 15/019,767by Yerramalli et al., entitled “Techniques for Managing a Plurality ofRadio Access Technologies Accessing a Shared Radio Frequency SpectrumBand,” filed Feb. 9, 2016, which claims priority to U.S. ProvisionalPatent Application No. 62/114,912 by Yerramalli et al., entitled“Techniques for Managing a Plurality of Radio Access TechnologiesAccessing a Shared Radio Frequency Spectrum Band,” filed Feb. 11, 2015,each of which are assigned to the assignee hereof and expresslyincorporated by reference herein in their entirety.

BACKGROUND Field of the Disclosure

The present disclosure, for example, relates to wireless communicationsystems, and more particularly to techniques for managing a plurality ofradio access technologies (RATs) accessing a shared radio frequencyspectrum band.

Description of Related Art

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be multiple-accesssystems capable of supporting communication with multiple users bysharing the available system resources (e.g., time, frequency, andpower). Examples of such multiple-access systems include code-divisionmultiple access (CDMA) systems, time-division multiple access (TDMA)systems, frequency-division multiple access (FDMA) systems,single-carrier frequency-division multiple access (SC-FDMA) systems, andorthogonal frequency-division multiple access (OFDMA) systems.

By way of example, a wireless multiple-access communication system mayinclude a number of base stations, each simultaneously supportingcommunication for multiple communication devices, otherwise known asuser equipments (UEs). A base station may communicate with UEs ondownlink channels (e.g., for transmissions from a base station to a UE)and uplink channels (e.g., for transmissions from a UE to a basestation).

Some modes of communication may enable communication between a basestation and a UE over a shared radio frequency spectrum band (e.g., aradio frequency spectrum band shared with Wi-Fi nodes), or overdifferent radio frequency spectrum bands (e.g., a dedicated radiofrequency spectrum band and a shared radio frequency spectrum band) of acellular network. With increasing data traffic in cellular networks thatuse a dedicated (e.g., licensed) radio frequency spectrum band,offloading of at least some data traffic to a shared radio frequencyspectrum band may provide a cellular operator with opportunities forenhanced data transmission capacity. A shared radio frequency spectrumband may also provide service in areas where access to a dedicated radiofrequency spectrum band is unavailable.

Prior to gaining access to, and communicating over, a shared radiofrequency spectrum band, a base station or UE may perform a listenbefore talk (LBT) procedure to contend for access to the shared radiofrequency spectrum band. An LBT procedure may include performing a clearchannel assessment (CCA) procedure or extended CCA (ECCA) procedure todetermine whether a channel of the shared radio frequency spectrum bandis available. When it is determined that the channel of the shared radiofrequency spectrum band is available, the base station or UE maytransmit one or more channel reservation signals (e.g., one or morechannel usage beacon signals (CUBS)) over the channel, to reserve thechannel. In some examples, the channel reservation signal(s) may betransmitted over the channel until a next subframe boundary, at whichtime a data or control transmission may be made over the channel.

SUMMARY

The present disclosure, for example, relates to one or more techniquesfor managing a plurality of RATs accessing a shared radio frequencyspectrum band. In some examples, the techniques may pertain to managinga co-existence of base stations and UEs communicating over a sharedradio frequency spectrum band using a wireless wide area network (WWAN)RAT (e.g., a cellular RAT), and Wi-Fi access points and Wi-Fi stationscommunicating over the shared radio frequency spectrum band using awireless local area network (WLAN) RAT (e.g., a Wi-Fi RAT). Co-existencemanagement may be necessary because the nodes using the Wi-Fi RAT mayuse different techniques than the nodes using the cellular RAT tocontend for access to the shared radio frequency spectrum band. Forexample, the Wi-Fi nodes (e.g., the Wi-Fi access points and Wi-Fistations) may use Carrier Sense Multiple Access with Collision Avoidance(CSMA/CA) techniques to contend for access to the shared radio frequencyspectrum band, while the cellular nodes (e.g., the base stations andUEs) may use LBT procedures for load-based equipment (LBE) to contendfor access to the shared radio frequency spectrum band. Depending onaccess conditions, the use of these different access techniques may givean access advantage to the Wi-Fi nodes or the cellular nodes. Oneadvantage that cellular nodes may have over Wi-Fi nodes is their non-useof an exponential backoff mechanism. That is, when a Wi-Fi node fails tosuccessfully contend for access to the shared radio frequency spectrumband, or when in-process communications of the Wi-Fi node areinterrupted, an exponential backoff mechanism (e.g., a mechanism thatcauses the Wi-Fi node to increase the length of a wait time beforecontending for access to the shared radio frequency spectrum band again)may be triggered at the Wi-Fi node. Techniques described in the presentdisclosure may enable cellular nodes to avoid triggering the exponentialbackoff mechanisms of Wi-Fi nodes under some conditions.

In one example, a method for wireless communication is described. Themethod may include sensing an indication of first RAT communicationsoccupying a shared radio frequency spectrum band, and configuring, inresponse to the sensing, at least one parameter of a second RAT used bya device to contend for access to the shared radio frequency spectrumband.

In some examples of the method, the first RAT may include a Wi-Fi RATand the second RAT may include a cellular RAT. In some examples of themethod, configuring the at least one parameter of the second RAT mayinclude configuring a range of numbers from which a random number isselected, where the random number determines a number of CCA slots overwhich the device performs an extended CCA procedure. In some examples,configuring the range of numbers may include at least one of: increasinga lower bound of the range of numbers, or increasing an upper bound ofthe range of numbers, or a combination thereof.

In some examples of the method, configuring the at least one parameterof the second RAT may include identifying a number of consecutive CCAslots for which the shared radio frequency spectrum band is availablebefore the device wins contention for access to the shared radiofrequency spectrum band. In some of these examples, the identifiednumber of CCA slots may be a last number of CCA slots in which anextended CCA procedure is performed when the device has not woncontention for access to the shared radio frequency spectrum band.

In some examples of the method, configuring the at least one parameterof the second RAT may include configuring a CCA energy detectionthreshold for at least one CCA slot in which at least one CCA procedureis performed. In some examples, the method may include configuring thedevice to sense an energy level of the shared radio frequency spectrumband following a period in which the shared radio frequency spectrumband is occupied. In these latter examples, configuring the at least oneparameter of the second RAT may include configuring a CCA energydetection threshold based at least in part on the sensed energy;configuring the device to perform a number of CCA procedures based atleast in part on the CCA energy detection threshold, where the number ofCCA procedures may be performed in a set of CCA slots; and configuringthe device to win contention for access to the shared radio frequencyspectrum band when the shared radio frequency spectrum band isdetermined to be available for a subset of CCA slots included in the setof CCA slots.

In some examples of the method, configuring the at least one parameterof the second RAT may include increasing a duration of a last CCA slotin which an extended CCA procedure is performed. In some examples of themethod, configuring the at least one parameter of the second RAT mayinclude configuring the device to perform a plurality of extended CCAprocedures to contend for access to the shared radio frequency spectrumband. In some examples of the method, the plurality of extended CCAprocedures may include a first extended CCA procedure followed by asecond extended CCA procedure. In some examples, the first extended CCAprocedure may be configured to be performed over a first number of CCAslots and the second extended CCA procedure may be configured to beperformed over a second number of CCA slots.

In some examples of the method, configuring the at least one parameterof the second RAT may include configuring a deferment period for thedevice to wait, upon determining the shared radio frequency spectrumband is unavailable, before performing an additional number of CCAprocedures, and configuring the device to win contention for access tothe shared radio frequency spectrum band upon determining the sharedradio frequency spectrum band is available for each of the additionalnumber of CCA procedures.

In some examples of the method, the indication of first RATcommunications may be based at least in part on a number of transmittersdetected within an energy detection range of the device. In someexamples, the indication of first RAT communications may be based atleast in part on a failure rate of transmissions for which feedback isreported. In some examples, the indication of first RAT communicationsmay be based at least in part on an erasure rate for transmissions forwhich an error is not reported. In some examples, the indication offirst RAT communications may be based at least in part on a variancebetween a supported modulation and coding scheme (MCS) and an MCSactually used. In some examples of the method, the device may includeone of a base station or a UE, and the identifying and configuring maybe performed by the one of the base station or the UE.

In an example, an apparatus for wireless communication is described. Inone configuration, the apparatus may include means for sensing anindication of first RAT communications occupying a shared radiofrequency spectrum band, and means for configuring, in response to thesensing, at least one parameter of a second RAT used by a device tocontend for access to the shared radio frequency spectrum band. In someexamples, the apparatus may further include means for implementing oneor more aspects of the method for wireless communication described abovewith respect to the first set of illustrative examples.

In an example, an apparatus for wireless communication is described. Inone configuration, the apparatus may include a processor, memory inelectronic communication with the processor, and instructions stored inthe memory. The instructions may be executable by the processor to sensean indication of first RAT communications occupying a shared radiofrequency spectrum band, and configure, in response to the sensing, atleast one parameter of a second RAT used by a device to contend foraccess to the shared radio frequency spectrum band. In some examples,the instructions may also be executable by the processor to implementone or more aspects of the method for wireless communication describedabove with respect to the first set of illustrative examples.

In an example, a non-transitory computer-readable medium storingcomputer-executable code for wireless communication is described. In oneconfiguration, the code may be executable by a processor to sense anindication of first RAT communications occupying a shared radiofrequency spectrum band, and configure, in response to the sensing, atleast one parameter of a second RAT used by a device to contend foraccess to the shared radio frequency spectrum band. In some examples,the non-transitory computer-readable medium may also include code toimplement one or more aspects of the method for wireless communicationdescribed above with respect to the first set of illustrative examples.

In an example, a method for wireless communication is described. In oneconfiguration, the method may include randomly selecting a number from arange of numbers extending between a lower bound and an upper bound;contending for access to a shared radio frequency spectrum band byperforming an extended CCA procedure over a plurality of CCA slots,where the plurality of CCA slots include a first number of CCA slotsequal to the upper bound; and winning contention for access to theshared radio frequency spectrum band after determining, while performingthe extended CCA procedure, that the shared radio frequency spectrumband is available for a second number of CCA slots equal to the randomlyselected number.

In some examples, the method may include discontinuing the extended CCAprocedure and failing to win contention for access to the shared radiofrequency spectrum band after determining, while performing the extendedCCA procedure, that the shared radio frequency spectrum band isunavailable for a third number of CCA slots equal to the first number ofCCA slots, less the randomly selected number, plus one.

In an example, another apparatus for wireless communication isdescribed. In one configuration, the apparatus may include means forrandomly selecting a number from a range of numbers extending between alower bound and an upper bound; means for contending for access to ashared radio frequency spectrum band by performing an extended CCAprocedure over a plurality of CCA slots, where the plurality of CCAslots include a first number of CCA slots equal to the upper bound; andmeans for winning contention for access to the shared radio frequencyspectrum band after determining, while performing the extended CCAprocedure, that the shared radio frequency spectrum band is availablefor a second number of CCA slots equal to the randomly selected number.In some examples, the apparatus may further include means forimplementing one or more aspects of the method for wirelesscommunication described above with respect to the fifth set ofillustrative examples.

In an example, another apparatus for wireless communication isdescribed. In one configuration, the apparatus may include a processor,memory in electronic communication with the processor, and instructionsstored in the memory. The instructions may be executable by theprocessor to randomly select a number from a range of numbers extendingbetween a lower bound and an upper bound; to contend for access to ashared radio frequency spectrum band by performing an extended CCAprocedure over a plurality of CCA slots, where the plurality of CCAslots include a first number of CCA slots equal to the upper bound; andto win contention for access to the shared radio frequency spectrum bandafter determining, while performing the extended CCA procedure, that theshared radio frequency spectrum band is available for a second number ofCCA slots equal to the randomly selected number. In some examples, theinstructions may also be executable by the processor to implement one ormore aspects of the method for wireless communication described abovewith respect to the fifth set of illustrative examples.

In an example, another non-transitory computer-readable medium storingcomputer-executable code for wireless communication is described. In oneconfiguration, the code may be executable by a processor to randomlyselect a number from a range of numbers extending between a lower boundand an upper bound; contend for access to a shared radio frequencyspectrum band by performing an extended CCA procedure over a pluralityof CCA slots, where the plurality of CCA slots include a first number ofCCA slots equal to the upper bound; and win contention for access to theshared radio frequency spectrum band after determining, while performingthe extended CCA procedure, that the shared radio frequency spectrumband is available for a second number of CCA slots equal to the randomlyselected number. In some examples, the non-transitory computer-readablemedium may also include code to implement one or more aspects of themethod for wireless communication described above with respect to thefirst set of illustrative examples.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description, and not as a definition of the limits ofthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the following drawings. In theappended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 illustrates an example of a wireless communication system, inaccordance with various aspects of the disclosure;

FIG. 2 shows a wireless communication system in which LTE/LTE-A may bedeployed under different scenarios using a shared radio frequencyspectrum band, in accordance with various aspects of the presentdisclosure;

FIG. 3 shows an example of a wireless communication over a shared radiofrequency spectrum band, in accordance with various aspects of thepresent disclosure;

FIG. 4A shows an example of a CCA procedure performed by a transmittingapparatus when contending for access to a shared radio frequencyspectrum band, in accordance with various aspects of the presentdisclosure;

FIG. 4B shows an example of an ECCA procedure performed by atransmitting apparatus when contending for access to an unlicensed radiofrequency spectrum band, in accordance with various aspects of thepresent disclosure;

FIG. 5 illustrates communications between a Wi-Fi access point and aWi-Fi station, in the vicinity of a base station, in accordance withvarious aspects of the present disclosure;

FIG. 6 shows various Wi-Fi transmission formats involving a Wi-Fi accesspoint and a Wi-Fi station, in accordance with various aspects of thepresent disclosure;

FIG. 7 shows an exemplary timeline of communications over a shared radiofrequency spectrum band, between a Wi-Fi access point and a Wi-Fistation, as an apparatus (e.g., a base station or UE) contends foraccess to the shared radio frequency spectrum band, in accordance withvarious aspects of the present disclosure;

FIG. 8 shows an exemplary timeline of communications over a shared radiofrequency spectrum band, between a Wi-Fi access point and a Wi-Fistation, as an apparatus (e.g., a base station or UE) contends foraccess to the shared radio frequency spectrum band, in accordance withvarious aspects of the present disclosure;

FIG. 9 shows an exemplary timeline of communications over a shared radiofrequency spectrum band, between a Wi-Fi access point and a Wi-Fistation, as an apparatus (e.g., a base station or UE) contends foraccess to the shared radio frequency spectrum band, in accordance withvarious aspects of the present disclosure;

FIG. 10 shows an exemplary timeline of CCA slots in which an ECCAprocedure may be performed by an apparatus (e.g., a base station or UE)contending for access to a shared radio frequency spectrum band, inaccordance with various aspects of the present disclosure;

FIG. 11 shows exemplary timelines of CCA slots in which a first ECCAprocedure and a second ECCA procedure may be performed by an apparatus(e.g., a base station or UE) contending for access to a shared radiofrequency spectrum band, in accordance with various aspects of thepresent disclosure;

FIG. 12 shows an exemplary timeline of communications over a sharedradio frequency spectrum band, between a Wi-Fi access point and a Wi-Fistation, as an apparatus (e.g., a base station or UE) contends foraccess to the shared radio frequency spectrum band, in accordance withvarious aspects of the present disclosure;

FIG. 13 shows an exemplary timeline of CCA slots in which an ECCAprocedure may be performed by an apparatus (e.g., a base station or UE)contending for access to a shared radio frequency spectrum band, inaccordance with various aspects of the present disclosure;

FIG. 14 shows a block diagram of an apparatus for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure;

FIG. 15 shows a block diagram of an apparatus for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure;

FIG. 16 shows a block diagram of an apparatus for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure;

FIG. 17 shows a block diagram of an apparatus for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure;

FIG. 18 shows a block diagram of a base station (e.g., a base stationforming part or all of an eNB) for use in wireless communication, inaccordance with various aspects of the present disclosure;

FIG. 19 shows a block diagram of a UE for use in wireless communication,in accordance with various aspects of the present disclosure;

FIG. 20 is a flow chart illustrating an exemplary method for wirelesscommunication, in accordance with various aspects of the presentdisclosure;

FIG. 21 is a flow chart illustrating an exemplary method for wirelesscommunication, in accordance with various aspects of the presentdisclosure;

FIG. 22 is a flow chart illustrating an exemplary method for wirelesscommunication, in accordance with various aspects of the presentdisclosure; and

FIG. 23 is a flow chart illustrating an exemplary method for wirelesscommunication, in accordance with various aspects of the presentdisclosure.

DETAILED DESCRIPTION

Techniques are described in which a shared radio frequency spectrum bandis used for at least a portion of communications over a wirelesscommunication system. In some examples, the shared radio frequencyspectrum band may be used for LTE/LTE-A communications. The shared radiofrequency spectrum band may be used in combination with, or independentfrom, a dedicated radio frequency spectrum band. The dedicated radiofrequency spectrum band may be a radio frequency spectrum band for whichtransmitting apparatuses may not contend for access because the radiofrequency spectrum band is licensed to particular users, such as alicensed radio frequency spectrum band usable for LTE/LTE-Acommunications. The shared radio frequency spectrum band may be a radiofrequency spectrum band for which a device may need to contend foraccess (e.g., a radio frequency spectrum band that is available forunlicensed use, such as Wi-Fi use, or a radio frequency spectrum bandthat is available for use by multiple operators in an equally shared orprioritized manner).

With increasing data traffic in cellular networks that use a dedicatedradio frequency spectrum band, offloading of at least some data trafficto a shared radio frequency spectrum band may provide a cellularoperator (e.g., an operator of a public land mobile network (PLMN) or acoordinated set of base stations defining a cellular network, such as anLTE/LTE-A network) with opportunities for enhanced data transmissioncapacity. Use of a shared radio frequency spectrum band may also provideservice in areas where access to a dedicated radio frequency spectrumband is unavailable. As noted above, before communicating over a sharedradio frequency spectrum band, transmitting apparatuses may perform anLBT procedure to gain access to the medium. Such an LBT procedure mayinclude performing a CCA procedure (or ECCA procedure) to determinewhether a channel of the shared radio frequency spectrum band isavailable. When it is determined that the channel of the shared radiofrequency spectrum band is available, a CUBS may be transmitted toreserve the channel. When it is determined that a channel is notavailable, a CCA procedure (or ECCA procedure) may be performed for thechannel again at a later time.

Under some scenarios, the non-use of an exponential backoff mechanism bycellular nodes (e.g., base stations and UEs) may provide the cellularnodes an unfair advantage when contending for access to the shared radiofrequency spectrum band. Techniques described in the present disclosuremay enable cellular nodes to avoid triggering the exponential backoffmechanisms of Wi-Fi nodes under some conditions.

Under some scenarios, communications between the Wi-Fi access point andWi-Fi station(s) may be separated by a short interframe spacing (SIFS).A base station or UE contending for access to a shared radio frequencyspectrum band over which the Wi-Fi communications are carried mayinterpret the SIFS as an indication that the shared radio frequencyspectrum band is available (e.g., unoccupied). Also, when the Wi-Fiaccess point or one or more Wi-Fi stations are outside the energydetection range of the base station or UE, the base station or UE mayinterpret Wi-Fi communications as being complete, and may assume thatthe shared radio frequency spectrum band is available when it is stillneeded for completion of a Wi-Fi communication. Techniques describedherein may include improved configurations of CCA that may beimplemented by cellular nodes.

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in other examples.

FIG. 1 illustrates an example of a wireless communication system 100, inaccordance with various aspects of the disclosure. The wirelesscommunication system 100 may include base stations 105, UEs 115, and acore network 130. The core network 130 may provide user authentication,access authorization, tracking, Internet Protocol (IP) connectivity, andother access, routing, or mobility functions. The base stations 105 mayinterface with the core network 130 through backhaul links 132 (e.g.,S1, etc.) and may perform radio configuration and scheduling forcommunication with the UEs 115, or may operate under the control of abase station controller (not shown). In various examples, the basestations 105 may communicate, either directly or indirectly (e.g.,through core network 130), with each other over backhaul links 134(e.g., X1, etc.), which may be wired or wireless communication links.

The base stations 105 may wirelessly communicate with the UEs 115 viaone or more base station antennas. Each of the base station 105 sitesmay provide communication coverage for a respective geographic coveragearea 110. In some examples, a base station 105 may be referred to as abase transceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a Home NodeB, a Home eNodeB, orsome other suitable terminology. The geographic coverage area 110 for abase station 105 may be divided into sectors making up a portion of thecoverage area (not shown). The wireless communication system 100 mayinclude base stations 105 of different types (e.g., macro or small cellbase stations). There may be overlapping geographic coverage areas 110for different technologies.

In some examples, the wireless communication system 100 may include anLTE/LTE-A network. In LTE/LTE-A networks, the term evolved Node B (eNB)may be used to describe the base stations 105, while the term UE may beused to describe the UEs 115. The wireless communication system 100 maybe a Heterogeneous LTE/LTE-A network in which different types of eNBsprovide coverage for various geographical regions. For example, each eNBor base station 105 may provide communication coverage for a macro cell,a small cell, or other types of cell. The term “cell” is a 3GPP termthat can be used to describe a base station, a carrier or componentcarrier associated with a base station, or a coverage area (e.g.,sector, etc.) of a carrier or base station, depending on context.

A macro cell may cover a relatively large geographic area (e.g., severalkilometers in radius) and may allow unrestricted access by UEs withservice subscriptions with the network provider. A small cell may be alower-powered base station, as compared with a macro cell that mayoperate in the same or different (e.g., dedicated, shared, etc.) radiofrequency spectrum bands as macro cells. Small cells may include picocells, femto cells, and micro cells according to various examples. Apico cell may cover a relatively smaller geographic area and may allowunrestricted access by UEs with service subscriptions with the networkprovider. A femto cell also may cover a relatively small geographic area(e.g., a home) and may provide restricted access by UEs having anassociation with the femto cell (e.g., UEs in a closed subscriber group(CSG), UEs for users in the home, and the like). An eNB for a macro cellmay be referred to as a macro eNB. An eNB for a small cell may bereferred to as a small cell eNB, a pico eNB, a femto eNB or a home eNB.An eNB may support one or multiple (e.g., two, three, four, and thelike) cells (e.g., component carriers).

The wireless communication system 100 may support synchronous orasynchronous operation. For synchronous operation, the base stations mayhave similar frame timing, and transmissions from different basestations may be approximately aligned in time. For asynchronousoperation, the base stations may have different frame timing, andtransmissions from different base stations may not be aligned in time.The techniques described herein may be used for either synchronous orasynchronous operations.

The communication networks that may accommodate some of the variousdisclosed examples may be packet-based networks that operate accordingto a layered protocol stack. In the user plane, communications at thebearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based.A Radio Link Control (RLC) layer may perform packet segmentation andreassembly to communicate over logical channels. A Medium Access Control(MAC) layer may perform priority handling and multiplexing of logicalchannels into transport channels. The MAC layer may also use Hybrid ARQ(HARD) to provide retransmission at the MAC layer to improve linkefficiency. In the control plane, the Radio Resource Control (RRC)protocol layer may provide establishment, configuration, and maintenanceof an RRC connection between a UE 115 and the base stations 105 or corenetwork 130 supporting radio bearers for the user plane data. At thephysical (PHY) layer, the transport channels may be mapped to physicalchannels.

The UEs 115 may be dispersed throughout the wireless communicationsystem 100, and each UE 115 may be stationary or mobile. A UE 115 mayalso include or be referred to by those skilled in the art as a mobilestation, a subscriber station, a mobile unit, a subscriber unit, awireless unit, a remote unit, a mobile device, a wireless device, awireless communications device, a remote device, a mobile subscriberstation, an access terminal, a mobile terminal, a wireless terminal, aremote terminal, a handset, a user agent, a mobile client, a client, orsome other suitable terminology. A UE 115 may be a cellular phone, apersonal digital assistant (PDA), a wireless modem, a wirelesscommunication device, a handheld device, a tablet computer, a laptopcomputer, a cordless phone, a wireless local loop (WLL) station, or thelike. A UE may be able to communicate with various types of basestations and network equipment, including macro eNBs, small cell eNBs,relay base stations, and the like.

The communication links 125 shown in wireless communication system 100may include downlink (DL) transmissions, from a base station 105 to a UE115, or uplink (UL) transmissions, from a UE 115 to a base station 105.The downlink transmissions may also be called forward linktransmissions, while the uplink transmissions may also be called reverselink transmissions.

In some examples, each communication link 125 may include one or morecarriers, where each carrier may be a signal made up of multiplesub-carriers (e.g., waveform signals of different frequencies) modulatedaccording to the various radio technologies described above. Eachmodulated signal may be sent on a different sub-carrier and may carrycontrol information (e.g., reference signals, control channels, etc.),overhead information, user data, etc. The communication links 125 maytransmit bidirectional communications using a frequency domain duplexing(FDD) operation (e.g., using paired spectrum resources) or a time domainduplexing (TDD) operation (e.g., using unpaired spectrum resources).Frame structures for FDD operation (e.g., frame structure type 1) andTDD operation (e.g., frame structure type 2) may be defined.

In some examples of the wireless communication system 100, base stations105 or UEs 115 may include multiple antennas for employing antennadiversity schemes to improve communication quality and reliabilitybetween base stations 105 and UEs 115. Additionally or alternatively,base stations 105 or UEs 115 may employ multiple-input, multiple-output(MIMO) techniques that may take advantage of multi-path environments totransmit multiple spatial layers carrying the same or different codeddata.

The wireless communication system 100 may support operation on multiplecells or carriers, a feature which may be referred to as carrieraggregation (CA) or dual-connectivity operation. A carrier may also bereferred to as a component carrier (CC), a layer, a channel, etc. Theterms “carrier,” “component carrier,” “cell,” and “channel” may be usedinterchangeably herein. A UE 115 may be configured with multipledownlink CCs and one or more uplink CCs for carrier aggregation. Carrieraggregation may be used with both FDD and TDD component carriers.

In some examples, the wireless communication system 100 may supportoperation over a dedicated radio frequency spectrum (e.g., a radiofrequency spectrum band for which transmitting apparatuses may notcontend for access because the radio frequency spectrum band is licensedto particular users for particular uses, such as a licensed radiofrequency spectrum band usable for LTE/LTE-A communications) or a sharedradio frequency spectrum band (e.g., a radio frequency spectrum band forwhich transmitting apparatuses may need to contend for access (e.g., aradio frequency spectrum band that is available for unlicensed use, suchas Wi-Fi use, or a radio frequency spectrum band that is available foruse by multiple operators in an equally shared or prioritized manner)).

The shared radio frequency spectrum band may be shared with nodescommunicating in accordance with a different RAT, such as Wi-Fi nodescommunicating in accordance with a Wi-Fi RAT. By way of example, FIG. 1illustrates a Wi-Fi network 140 including a Wi-Fi access point 135 and anumber of Wi-Fi stations 145. The Wi-Fi access point 135 and Wi-Fistations 145 may communicate with one another in the vicinity of thebase stations 105 and UEs 115, and under some scenarios, communicationsbetween the Wi-Fi access point 135 and Wi-Fi stations 145 may interferewith, or be interfered with, communications between the base stations105 and UEs 115.

FIG. 2 shows a wireless communication system 200 in which LTE/LTE-A maybe deployed under different scenarios using a shared radio frequencyspectrum band, in accordance with various aspects of the presentdisclosure. More specifically, FIG. 2 illustrates examples of asupplemental downlink mode (also referred to as a licensed assistedaccess mode), a carrier aggregation mode, and a standalone mode in whichLTE/LTE-A is deployed using a shared radio frequency spectrum band. Thewireless communication system 200 may be an example of portions of thewireless communication system 100 described with reference to FIG. 1.Moreover, a first base station 205 and a second base station 205-a maybe examples of aspects of one or more of the base stations 105 describedwith reference to FIG. 1, while a first UE 215, a second UE 215-a, athird UE 215-b, and a fourth UE 215-c may be examples of aspects of oneor more of the UEs 115 described with reference to FIG. 1.

In the example of a supplemental downlink mode (e.g., a licensedassisted access mode) in the wireless communication system 200, thefirst base station 205 may transmit OFDMA waveforms to the first UE 215using a downlink channel 220. The downlink channel 220 may be associatedwith a frequency F1 in a shared radio frequency spectrum band. The firstbase station 205 may transmit OFDMA waveforms to the first UE 215 usinga first bidirectional link 225 and may receive SC-FDMA waveforms fromthe first UE 215 using the first bidirectional link 225. The firstbidirectional link 225 may be associated with a frequency F4 in adedicated radio frequency spectrum band. The downlink channel 220 in theshared radio frequency spectrum band and the first bidirectional link225 in the dedicated radio frequency spectrum band may operatecontemporaneously. The downlink channel 220 may provide a downlinkcapacity offload for the first base station 205. In some examples, thedownlink channel 220 may be used for unicast services (e.g., addressedto one UE) or for multicast services (e.g., addressed to several UEs).This scenario may occur with any service provider (e.g., a mobilenetwork operator (MNO)) that uses a dedicated radio frequency spectrumband and needs to relieve some of the traffic or signaling congestion.

In one example of a carrier aggregation mode in the wirelesscommunication system 200, the first base station 205 may transmit OFDMAwaveforms to the second UE 215-a using a second bidirectional link 230and may receive OFDMA waveforms, SC-FDMA waveforms, or resource blockinterleaved FDMA waveforms from the second UE 215-a using the secondbidirectional link 230. The second bidirectional link 230 may beassociated with the frequency F1 in the shared radio frequency spectrumband. The first base station 205 may also transmit OFDMA waveforms tothe second UE 215-a using a third bidirectional link 235 and may receiveSC-FDMA waveforms from the second UE 215-a using the third bidirectionallink 235. The third bidirectional link 235 may be associated with afrequency F2 in a dedicated radio frequency spectrum band. The secondbidirectional link 230 may provide a downlink and uplink capacityoffload for the first base station 205. Like the supplemental downlink(e.g., the licensed assisted access mode) described above, this scenariomay occur with any service provider (e.g., MNO) that uses a dedicatedradio frequency spectrum band and needs to relieve some of the trafficor signaling congestion.

In another example of a carrier aggregation mode in the wirelesscommunication system 200, the first base station 205 may transmit OFDMAwaveforms to the third UE 215-b using a fourth bidirectional link 240and may receive OFDMA waveforms, SC-FDMA waveforms, or resource blockinterleaved waveforms from the third UE 215-b using the fourthbidirectional link 240. The fourth bidirectional link 240 may beassociated with a frequency F3 in the shared radio frequency spectrumband. The first base station 205 may also transmit OFDMA waveforms tothe third UE 215-b using a fifth bidirectional link 245 and may receiveSC-FDMA waveforms from the third UE 215-b using the fifth bidirectionallink 245. The fifth bidirectional link 245 may be associated with thefrequency F2 in the dedicated radio frequency spectrum band. The fourthbidirectional link 240 may provide a downlink and uplink capacityoffload for the first base station 205. This example and those providedabove are presented for illustrative purposes and there may be othersimilar modes of operation or deployment scenarios that combineLTE/LTE-A in a dedicated radio frequency spectrum band and use a sharedradio frequency spectrum band for capacity offload.

As described above, one type of service provider that may benefit fromthe capacity offload offered by using LTE/LTE-A in a shared radiofrequency spectrum band is a traditional MNO having access rights to anLTE/LTE-A dedicated radio frequency spectrum band. For these serviceproviders, an operational example may include a bootstrapped mode (e.g.,supplemental downlink (e.g., licensed assisted access), carrieraggregation) that uses the LTE/LTE-A primary component carrier (PCC) onthe dedicated radio frequency spectrum band and at least one secondarycomponent carrier (SCC) on the shared radio frequency spectrum band.

In the carrier aggregation mode, data and control may, for example, becommunicated in the dedicated radio frequency spectrum band (e.g., viafirst bidirectional link 225, third bidirectional link 235, and fifthbidirectional link 245) while data may, for example, be communicated inthe shared radio frequency spectrum band (e.g., via second bidirectionallink 230 and fourth bidirectional link 240). The carrier aggregationmechanisms supported when using a shared radio frequency spectrum bandmay fall under a hybrid frequency division duplexing-time divisionduplexing (FDD-TDD) carrier aggregation or a TDD-TDD carrier aggregationwith different symmetry across component carriers.

In one example of a standalone mode in the wireless communication system200, the second base station 205-a may transmit OFDMA waveforms to thefourth UE 215-c using a bidirectional link 250 and may receive OFDMAwaveforms, SC-FDMA waveforms, or resource block interleaved FDMAwaveforms from the fourth UE 215-c using the bidirectional link 250. Thebidirectional link 250 may be associated with the frequency F3 in theshared radio frequency spectrum band. The standalone mode may be used innon-traditional wireless access scenarios, such as in-stadium access(e.g., unicast, multicast). An example of a type of service provider forthis mode of operation may be a stadium owner, cable company, eventhost, hotel, enterprise, or large corporation that does not have accessto a dedicated radio frequency spectrum band.

In some examples, a transmitting apparatus such as one of the basestations 105, 205, or 205-a described with reference to FIG. 1 or 2, orone of the UEs 115, 215, 215-a, 215-b, or 215-c described with referenceto FIG. 1 or 2, may use a gating interval to gain access to a channel ofa shared radio frequency spectrum band (e.g., to a physical channel ofthe shared radio frequency spectrum band). In some examples, the gatinginterval may be periodic. For example, the periodic gating interval maybe synchronized with at least one boundary of an LTE/LTE-A radiointerval. The gating interval may define the application of acontention-based protocol, such as an LBT protocol based on the LBTprotocol specified in European Telecommunications Standards Institute(ETSI) (EN 301 893). When using a gating interval that defines theapplication of an LBT protocol, the gating interval may indicate when atransmitting apparatus needs to perform a contention procedure (e.g., anLBT procedure) such as a clear channel assessment (CCA) procedure. Theoutcome of the CCA procedure may indicate to the transmitting apparatuswhether a channel of a shared radio frequency spectrum band is availableor in use for the gating interval (also referred to as an LBT radioframe). When a CCA procedure indicates that the channel is available fora corresponding LBT radio frame (e.g., “clear” for use), thetransmitting apparatus may reserve or use the channel of the sharedradio frequency spectrum band during part or all of the LBT radio frame.When the CCA procedure indicates that the channel is not available(e.g., that the channel is in use or reserved by another transmittingapparatus), the transmitting apparatus may be prevented from using thechannel during the LBT radio frame.

FIG. 3 shows an example 300 of a wireless communication 310 over ashared radio frequency spectrum band, in accordance with various aspectsof the present disclosure. In some examples, the wireless communication310 may include one or more component carriers, which componentcarrier(s) may be transmitted, for example, as part of a transmissionmade according to the supplemental downlink mode (e.g., the licensedassisted access mode), the carrier aggregation mode, or the standalonemode described with reference to FIG. 2.

In some examples, an LBT radio frame 315 of the wireless communication310 may have a duration of ten milliseconds and include a number ofdownlink (D) subframes 320, a number of uplink (U) subframes 325, andtwo types of special subframes, an S subframe 330 and an S′ subframe335. The S subframe 330 may provide a transition between downlinksubframes 320 and uplink subframes 325, while the S′ subframe 335 mayprovide a transition between uplink subframes 325 and downlink subframes320 and, in some examples, a transition between LBT radio frames.

During the S′ subframe 335, a downlink clear channel assessment (DCCA)procedure 345 may be performed by one or more base stations, such as oneor more of the base stations 105, 205, or 205-a described with referenceto FIG. 1 or 2, to reserve, for a period of time, a channel of theshared radio frequency spectrum band over which the wirelesscommunication 310 occurs. Following a successful DCCA procedure 345 by abase station, the base station may transmit a channel usage beaconsignal (CUBS) (e.g., a downlink CUBS (D-CUBS 350)) to provide anindication to other base stations or apparatuses (e.g., UEs, Wi-Fiaccess points, etc.) that the base station has reserved the channel. Insome examples, a D-CUBS 350 may be transmitted using a plurality ofinterleaved resource blocks. Transmitting a D-CUBS 350 in this mannermay enable the D-CUBS 350 to occupy at least some percentage of theavailable frequency bandwidth of the shared radio frequency spectrumband and satisfy one or more regulatory requirements (e.g., arequirement that transmissions over the shared radio frequency spectrumband occupy at least 80% of the available frequency bandwidth). TheD-CUBS 350 may in some examples take a form similar to that of anLTE/LTE-A cell-specific reference signal (CRS) or a channel stateinformation reference signal (CSI-RS). When the DCCA procedure 345fails, the D-CUBS 350 may not be transmitted.

The S′ subframe 335 may include a plurality of OFDM symbol periods(e.g., 14 OFDM symbol periods). A first portion of the S′ subframe 335may be used by a number of UEs as a shortened uplink (U) period. Asecond portion of the S′ subframe 335 may be used for the DCCA procedure345. A third portion of the S′ subframe 335 may be used by one or morebase stations that successfully contend for access to the channel of theshared radio frequency spectrum band as a downlink pilot time slot(DwPTS) or to transmit the D-CUBS 350.

During the S subframe 330, an uplink CCA (UCCA) procedure 365 may beperformed by one or more UEs, such as one or more of the UEs 115, 215,215-a, 215-b, or 215-c described above with reference to FIG. 1 or 2, toreserve, for a period of time, the channel over which the wirelesscommunication 310 occurs. Following a successful UCCA procedure 365 by aUE, the UE may transmit an uplink CUBS (U-CUBS 370) to provide anindication to other UEs or apparatuses (e.g., base stations, Wi-Fiaccess points, etc.) that the UE has reserved the channel. In someexamples, a U-CUBS 370 may be transmitted using a plurality ofinterleaved resource blocks. Transmitting a U-CUBS 370 in this mannermay enable the U-CUBS 370 to occupy at least a certain percentage of theavailable frequency bandwidth of the shared radio frequency spectrumband and satisfy one or more regulatory requirements (e.g., therequirement that transmissions over the shared radio frequency spectrumband occupy at least 80% of the available frequency bandwidth). TheU-CUBS 370 may in some examples take a form similar to that of anLTE/LTE-A CRS or CSI-RS. When the UCCA procedure 365 fails, the U-CUBS370 may not be transmitted.

The S subframe 330 may include a plurality of OFDM symbol periods (e.g.,14 OFDM symbol periods). A first portion of the S subframe 330 may beused by a number of base stations as a shortened downlink (D) period355. A second portion of the S subframe 330 may be used as a guardperiod (GP) 360. A third portion of the S subframe 330 may be used forthe UCCA procedure 365. A fourth portion of the S subframe 330 may beused by one or more UEs that successfully contend for access to thechannel of the shared radio frequency spectrum band as an uplink pilottime slot (UpPTS) or to transmit the U-CUBS 370.

In some examples, the DCCA procedure 345 or the UCCA procedure 365 mayinclude the performance of a CCA procedure during a single CCA slot. Inother examples, the DCCA procedure 345 or the UCCA procedure 365 mayinclude the performance of an extended CCA (ECCA) procedure. The ECCAprocedure may be performed over a plurality of CCA slots. The terms DCCAprocedure and UCCA procedure are therefore intended to be broad enoughto cover the performance of either a CCA procedure or an ECCA procedure.The selection of a CCA procedure or an ECCA procedure, for performanceby a base station or a UE during an LBT radio frame, may be based on LBTrules. In some cases, the term CCA procedure may be used in thisdisclosure, in a general sense, to refer to either a CCA procedure or anECCA procedure.

By way of example, the LBT radio frame 315 has a DDDDDDSUUS' TDD framestructure. In other examples, an LBT radio frame may have a differentTDD frame structure. For example, an LBT radio frame may have one of theTDD frame structures used in enhanced interference mitigation andtraffic adaptation (eIMTA).

FIG. 4A shows an example 400 of a CCA procedure 415 performed by atransmitting apparatus when contending for access to a shared radiofrequency spectrum band, in accordance with various aspects of thepresent disclosure. In some examples, the CCA procedure 415 may be anexample of the DCCA procedure 345 or UCCA procedure 365 described withreference to FIG. 3. The CCA procedure 415 may be performed over asingle CCA slot and have a fixed duration. In some examples, the CCAprocedure 415 may be performed in accordance with an LBT-frame basedequipment (LBT-FBE) protocol (e.g., the LBT-FBE protocol described by EN301 893). Following the CCA procedure 415, a CUBS 420 may betransmitted, followed by a data transmission (e.g., an uplinktransmission or a downlink transmission). By way of example, the datatransmission may have an intended duration 405 of three subframes and anactual duration 410 of three subframes.

FIG. 4B shows an example 450 of an ECCA procedure 465 performed by atransmitting apparatus when contending for access to an unlicensed radiofrequency spectrum band, in accordance with various aspects of thepresent disclosure. In some examples, the ECCA procedure 465 may be anexample of the DCCA procedure 345 or UCCA procedure 365 described withreference to FIG. 3. The ECCA procedure 465 may be performed over aplurality of q CCA slots, and in some examples may require that theshared radio frequency spectrum band be available during a randomnumber, N, of the q CCA slots before the transmitting apparatus may wincontention for access to the shared radio frequency spectrum band. Insome examples, the ECCA procedure 465 may be performed after theperformance of a CCA procedure 415 (as described with reference to FIG.4A) is unsuccessful. In some examples, the ECCA procedure 465 may beperformed in accordance with an LBT-load based equipment (LBT-LBE)protocol (e.g., the LBT-LBE protocol described by EN 301 893). The ECCAprocedure 465 may provide a greater likelihood of winning contention toaccess the unlicensed radio frequency spectrum band, but at a potentialcost of a shorter data transmission. Following the performance of asuccessful ECCA procedure 465, a CUBS 470 may be transmitted, followedby a data transmission. By way of example, the data transmission mayhave an intended duration 455 of three subframes and an actual duration460 of two subframes.

FIG. 5 illustrates communications between a Wi-Fi access point 535 and aWi-Fi station 545, in the vicinity of a base station 505, in accordancewith various aspects of the present disclosure. The Wi-Fi access point535 and Wi-Fi station 545 may be respective examples of aspects of theWi-Fi access point 135 and Wi-Fi station 145 described with reference toFIG. 1. The base station 505 may be an example of aspects of one or moreof the base stations 105, 205, or 205-a described with reference to FIG.1 or 2. The base station 505 may have an energy detection range 510.

When contending for access to a radio frequency spectrum band shared bythe base station 505, the Wi-Fi access point 535, and the Wi-Fi station545, the base station 505 may perform an LBT procedure (e.g., a CCAprocedure or an ECCA procedure) to contend for access to the sharedradio frequency spectrum band. The base station 505 may perform the LBTprocedure when the Wi-Fi access point 535 is communicating with theWi-Fi station 545, and the base station 505 may detect an energy of theWi-Fi access point's transmissions over the shard radio frequencyspectrum band and determine that the shared radio frequency spectrumband is unavailable. However, the base station 505 may perform an LBTprocedure when the Wi-Fi station 545 is communicating with the Wi-Fiaccess point 535, and the base station 505 may not detect an energy ofthe Wi-Fi station's transmissions over the shared radio frequencyspectrum band (e.g., because the Wi-Fi station 545 is outside the energydetection range 510 of the base station 505). Thus, when the Wi-Fiaccess point 535 and Wi-Fi station 545 take turns communicating in anuplink mode and a downlink mode, scenarios may arise in which the basestation 505 contends for access to the shared radio frequency spectrumband while the Wi-Fi station 545 is transmitting, and because the basestation 505 cannot detect the energy of the Wi-Fi station'stransmissions, the base station 505 may determine that the shared radiofrequency spectrum band is available and begin a transmission thatinterferes with the “in process” communications between the Wi-Fi accesspoint 535 and Wi-Fi station 545. The base station's transmission mayalso trigger an exponential backoff mode of the Wi-Fi access point 535or Wi-Fi station 545, which may make it relatively more difficult forthe Wi-Fi access point 535 or Wi-Fi station 545 to regain access to theshared radio frequency spectrum band. This may be unfair to the Wi-Finodes (e.g., the Wi-Fi access point 535 or the Wi-Fi station 545), andunder some conditions may be undesirable.

FIG. 6 shows various Wi-Fi transmission formats involving a Wi-Fi accesspoint (AP) and a Wi-Fi station (STA), in accordance with various aspectsof the present disclosure. In a first Wi-Fi transmission format 600, aWi-Fi access point transmits data (“Data”) that is acknowledged by aWi-Fi station (via an “ACK”). In a second Wi-Fi transmission format 610,a Wi-Fi access point transmits a request to send (RTS) signal that isacknowledged by a Wi-Fi station (e.g., via a clear to send (CTS)signal). The Wi-Fi access point may then transmit data (“Data”) that isacknowledged by an “ACK”. In a third Wi-Fi transmission format 620, aWi-Fi access point transmits a null data packet (NDP) announcementpacket followed by a NDP packet. Each of a first Wi-Fi station (STA_1),a second Wi-Fi station (STA_2), and a third Wi-Fi station (STA_3) maythen sequentially transmit a respective compressed beamforming packet(“Data”) which is followed by a beamforming poll packet (“Poll”)transmitted by the Wi-Fi access point. In a fourth Wi-Fi transmissionformat 630, a Wi-Fi access point may transmit multi-user MIMO (MU-MIMO)data to a plurality of Wi-Fi stations (e.g., STA_1, STA_2, and STA_3),followed by a sequence of block ACK requests (BARs), as part of a DLMU-MIMO transmission. Each BAR may be acknowledged by one of the Wi-Fistations in a respective block ACK (BA) transmission. In a fifth Wi-Fitransmission format 640, a Wi-Fi access point may transmit a DL triggerto a plurality of Wi-Fi stations (e.g., STA_1, STA_2, and STA_3), andeach of the Wi-Fi stations may respond with a data transmission (“Data”)as part of a UL MU-MIMO transmission.

In each of the first Wi-Fi transmission format 600, the second Wi-Fitransmission format 610, the third Wi-Fi transmission format 620, thefourth Wi-Fi transmission format 630, and the fifth Wi-Fi transmissionformat 640, changes in the direction of communications between the Wi-Fiaccess point and Wi-Fi station(s) may be separated by a short interframespacing (SIFS). A base station or UE contending for access to a sharedradio frequency spectrum band over which the Wi-Fi communications arecarried may interpret the SIFS as an indication that the shared radiofrequency spectrum band is available (e.g., idle). Also, when the Wi-Fiaccess point or one or more Wi-Fi stations are outside the energydetection range of the base station or UE, the base station or UE mayinterpret Wi-Fi communications as being complete, and may assume thatthe shared radio frequency spectrum band is available when it is stillneeded for completion of a Wi-Fi communication.

FIG. 7 shows an exemplary timeline 700 of communications over a sharedradio frequency spectrum band, between a Wi-Fi access point (AP) 735 anda Wi-Fi station (STA) 745, as an apparatus 705 (e.g., a base station(BS) or UE) contends for access to the shared radio frequency spectrumband, in accordance with various aspects of the present disclosure. TheWi-Fi access point 735 or the Wi-Fi station 745 may be an example ofaspects of one or more of the Wi-Fi access points 135 or 535 or Wi-Fistations 145 or 545, respectively, as described with reference to FIG. 1or 5. The apparatus 705 may be an example of aspects of one or more ofthe base stations 105, 205, 205-a, or 505, or one or more of the UEs115, 215, 215-a, 215-b, or 215-c, described with reference to FIG. 1, 2,or 5.

The communications between the Wi-Fi access point 735 and the Wi-Fistation 745 may assume, for example, any of the Wi-Fi transmissionformats shown in FIG. 6, and may switch between uplink transmissions anddownlink transmissions one or more times. By way of example, thecommunications between the Wi-Fi access point 735 and the Wi-Fi station745 are shown to assume the first Wi-Fi transmission format 600 shown inFIG. 6, in which data is transmitted from the Wi-Fi access point 735 tothe Wi-Fi station 745 during a period 710, and then an ACK istransmitted from the Wi-Fi station 745 to the Wi-Fi access point 735during a period 730 following a SIFS 720.

When the Wi-Fi access point 735 or the Wi-Fi station 745 is outside ofan energy detection range of the apparatus 705 (i.e., when the Wi-Fiaccess point 735 or the Wi-Fi station 745 is a hidden node with respectto the apparatus 705), the apparatus 705 may not detect thetransmissions of the hidden node. By way of example, FIG. 7 assumes thatthe Wi-Fi access point 735 is within an energy detection range of theapparatus 705 and the Wi-Fi station 745 is a hidden node with respect tothe apparatus 705, and thus, the apparatus 705 may detect the datatransmission during period 710 and determine that the shared radiofrequency spectrum band is occupied during a period 740, but may notdetect the ACK transmission by the Wi-Fi station 745 during period 730.As a result, when the apparatus 705 successfully completes an ECCAprocedure during period 750, the apparatus 705 may determine that theshared radio frequency spectrum band is available and begin transmittingdata during period 760. The apparatus' transmission of the data duringperiod 760 may collide with the Wi-Fi station's transmission of the ACKduring period 730 and interfere with the Wi-Fi access point's receipt ofthe ACK. The Wi-Fi access point's failure to receive or properly decodethe ACK may trigger the start or continuation of an exponential backoffby the Wi-Fi access point 735. When in exponential backoff mode, theWi-Fi access point 735 refrains from contending for access to the sharedradio frequency spectrum band for an extended period of time, whichperiod of time lengthens exponentially each time exponential backoff istriggered at the Wi-Fi access point 735.

As another example of an apparatus triggering an exponential backoff bya Wi-Fi access point, consider communications between a Wi-Fi accesspoint and a plurality of Wi-Fi stations according to the fourth Wi-Fitransmission format 630 (e.g., the DL MU-MIMO format) shown in FIG. 6.If any one of the Wi-Fi stations operates as a hidden node with respectto the apparatus, the apparatus may incorrectly determine that theshared radio frequency spectrum band is available (e.g., because itdetects an absence of transmissions on the shared radio frequencyspectrum band following a BAR transmission of the Wi-Fi access point)and transmit data that interferes with the Wi-Fi access point's receiptof a BA transmission from one of the Wi-Fi stations. When thetransmission of the apparatus causes the Wi-Fi access point to notreceive or not properly decode the BA transmission, exponential backoffmay be triggered at the Wi-Fi access point.

Under some scenarios, exponential backoff by a Wi-Fi node may betriggered in a manner that renders access to the shared radio frequencyspectrum band unfair. For example, the triggering of exponential backoffby a Wi-Fi node may enable an apparatus to access the shared radiofrequency spectrum band more frequently than the Wi-Fi node. Mechanismsimplemented by the apparatus (e.g., HARQ) may also enable the apparatusto complete its transmissions more effectively than the Wi-Fi node.

One technique for managing a plurality of RATs (e.g., a WWAN RAT and aWLAN RAT) to access a shared radio frequency spectrum band, for example,during a perceived gap in transmissions between a first Wi-Fi nodewithin energy detection range and a second Wi-Fi node that operates as ahidden node with respect to the apparatus, is to increase the value of Nthat determines the random number of N CCA slots for which a sharedradio frequency spectrum band needs to be available, when an ECCA isperformed by an apparatus, before a base station or UE may wincontention for access to a shared radio frequency spectrum band. A lowervalue of N (e.g., N=1 or 2) may enable an ECCA procedure to succeedafter determining that a shared radio frequency spectrum band isavailable for 1 or 2 CCA slots, despite the shared radio frequencyspectrum band being unavailable for q-N CCA slots (e.g., unavailable for30 or 31 slots when q=32). Such a low ratio of N:q may enable theapparatus to determine the shared radio frequency spectrum band isavailable based on its availability during a small number of CCA slotsrepresenting an incorrectly perceived gap in Wi-Fi transmissions betweenthe first Wi-Fi node and the second Wi-Fi node.

One way to effectively increase the value of N is to configure the rangeof numbers from which the random number N is selected. Configuring therange of numbers may include, for example, increasing a lower bound ofthe range of numbers, increasing an upper bound of the range of numbers,or increasing both the lower bound and the upper bound of the range ofnumbers. For example, instead of selecting N as a random number in therange of [1, q], N may be selected as a random number in the range of[N_(min), q+N_(min)], where N_(min)>1. Such a configuration may be madeper cell or per UE, and may be configured by a base station (for one ormore UEs) or a UE.

Another technique for managing a plurality of RATs (e.g., a WWAN RAT anda WLAN RAT) to access a shared radio frequency spectrum band, forexample, during a perceived gap in transmissions between a first Wi-Finode within energy detection range and a second Wi-Fi node that operatesas a hidden node with respect to the apparatus, is to configure theapparatus to identify a number of consecutive CCA slots for which theshared radio frequency spectrum band is available before winningcontention for access to the shared radio frequency spectrum band, asdescribed further with reference to FIG. 8.

FIG. 8 shows an exemplary timeline 800 of communications over a sharedradio frequency spectrum band, between a Wi-Fi access point (AP) 835 anda Wi-Fi station (STA) 845, as an apparatus 805 (e.g., a base station(BS) or UE) contends for access to the shared radio frequency spectrumband, in accordance with various aspects of the present disclosure. TheWi-Fi access point 835 or the Wi-Fi station 845 may be an example ofaspects of one or more of the Wi-Fi access points 135, 535, or 735 orWi-Fi stations 145, 545, or 745, respectively, as described withreference to FIG. 1, 5, or 7. The apparatus 805 may be an example ofaspects of one or more of the base stations 105, 205, 205-a, or 505, orone or more of the UEs 115, 215, 215-a, 215-b, or 215-c, described withreference to FIG. 1, 2, or 5. The apparatus 805 may also oralternatively be an example of aspects of the apparatus 705 describedwith reference to FIG. 7.

The communications between the Wi-Fi access point 835 and the Wi-Fistation 845 may assume, for example, any of the Wi-Fi transmissionformats shown in FIG. 6, and may switch between uplink transmissions anddownlink transmissions one or more times. For example, thecommunications between the Wi-Fi access point 835 and the Wi-Fi station845 are shown to assume the second Wi-Fi transmission format 610 shownin FIG. 6, in which a CTS transmission is transmitted from the Wi-Fiaccess point 835 to the Wi-Fi station 845 during a period 810; an RTStransmission is transmitted from the Wi-Fi station 845 to the Wi-Fiaccess point 835 during a period 830 following a first SIFS 820; data istransmitted from the Wi-Fi access point 835 to the Wi-Fi station 845during a period 850 following a second SIFS 840, and an ACK istransmitted from the Wi-Fi station 845 to the Wi-Fi access point 835during a period 865 following a third SIFS 860.

By way of example, FIG. 8 assumes that the Wi-Fi station 845 is a hiddennode with respect to the apparatus 805, and thus, the apparatus 805 maydetect the CTS transmission during period 810 and the data transmissionduring period 850 and determine that the shared radio frequency spectrumband is occupied during the period 870, the CCA slot 890, and the period895, but may not detect the RTS transmission during period 830 or theACK transmission during period 865. As a result, when the apparatus 805successfully completes an ECCA procedure during one of CCA slots 875,880, 885, or 890, the apparatus 805 may determine that the shared radiofrequency spectrum band is available and begin transmitting data thatinterferes with reception of the RTS transmission, the datatransmission, or the ACK transmission by the Wi-Fi access point 835 orWi-Fi station 845. The Wi-Fi access point's or Wi-Fi station's failureto receive or properly decode a transmission may trigger the start orcontinuation of an exponential backoff by the Wi-Fi access point 835 orWi-Fi station 845.

To decrease the chance that the apparatus 805 will successfully completean ECCA procedure during a perceived gap in the transmissions betweenthe Wi-Fi access point 835 and the Wi-Fi station 845, the apparatus 805may be configured to identify a number of consecutive CCA slots (e.g.,four CCA slots, including a first CCA slot 875, a second CCA slot 880, athird CCA slot 885, and a fourth CCA slot 890) for which the sharedradio frequency spectrum band is available before winning contention foraccess to the shared radio frequency spectrum band. In some examples,the consecutive number of CCA slots may be the last available CCA slotsbefore the apparatus 805 begins transmitting over the shared radiofrequency spectrum band. When an ECCA procedure to contend for access tothe shared radio frequency spectrum band is commenced before or duringthe occupied period 870, the number of consecutive CCA slots (e.g., thefirst CCA slot 875, the second CCA slot 880, the third CCA slot 885, andthe fourth CCA slot 890) may be a last available number of CCA slots inwhich the extended CCA procedure is performed. Alternatively, and whenthe ECCA procedure to contend for access to the shared radio frequencyspectrum band is commenced before or during the occupied period 870, thenumber of consecutive CCA slots (e.g., the first CCA slot 875, thesecond CCA slot 880, the third CCA slot 885, and the fourth CCA slot890) may include at least one of: a last number of CCA slots in whichthe extended CCA procedure is performed, or a number of CCA slots inwhich the extended CCA procedure is performed in combination with atleast one CCA slot following a last CCA slot in which the extended CCAprocedure is performed (e.g., the first CCA slot 875 and the second CCAslot 880 could be CCA slots in which the extended CCA procedure isperformed, and because the ECCA procedure concludes before the sharedradio frequency spectrum band has been determined available in theidentified number of consecutive slots, the ECCA procedure may becontinued, or one or more additional CCA procedures may be performed, inthe third CCA slot 885 and the fourth CCA slot 890.

When an ECCA procedure to contend for access to the shared radiofrequency spectrum band has already been performed and the apparatus 805is in an idle state with respect to the shared radio frequency spectrumband, the apparatus 805 may be configured to perform one or more CCAprocedures in a number of consecutive CCA slots, and determine theshared radio frequency spectrum band is available in each of the CCAslots, before beginning a transmission over the shared radio frequencyspectrum band.

As shown in FIG. 8, the number of consecutive CCA slots in which one ormore CCA procedures is performed is four consecutive CCA slots. Becausethe shared radio frequency spectrum band is only available in three ofthe four consecutive CCA slots, the apparatus 805 may not access theshared radio frequency spectrum band and will not interfere with theWi-Fi access point's reception of at least the RTS transmission, or theWi-Fi station's reception of at least the data transmitted by the Wi-Fiaccess point 835 during period 850. When the apparatus 805 determinesthat the shared radio frequency spectrum band is occupied (i.e.,unavailable) during one or more of the number of consecutive CCA slots,the apparatus 805 may be configured to refrain from accessing the sharedradio frequency spectrum band until a next occasion for performing anECCA procedure.

FIG. 9 shows an exemplary timeline 900 of communications over a sharedradio frequency spectrum band, between a Wi-Fi access point (AP) 935 anda Wi-Fi station (STA) 945, as an apparatus 905 (e.g., a base station(BS) or UE) contends for access to the shared radio frequency spectrumband, in accordance with various aspects of the present disclosure. TheWi-Fi access point 935 or the Wi-Fi station 945 may be an example ofaspects of one or more of the Wi-Fi access points 135, 535, 735, or 835or Wi-Fi stations 145, 545, 745, or 845, respectively, as described withreference to FIG. 1, 5, 7, or 8. The apparatus 905 may be an example ofaspects of one or more of the base stations 105, 205, 205-a, or 505, orone or more of the UEs 115, 215, 215-a, 215-b, or 215-c, described withreference to FIG. 1, 2, or 5. The apparatus 905 may also oralternatively be an example of aspects of one or more of the apparatuses705 or 805 described with reference to FIG. 7 or 8.

The communications between the Wi-Fi access point 935 and the Wi-Fistation 945 may assume, for example, any of the Wi-Fi transmissionformats shown in FIG. 6, and may switch between uplink transmissions anddownlink transmissions one or more times. By way of example, thecommunications between the Wi-Fi access point 935 and the Wi-Fi station945 are shown to assume the first Wi-Fi transmission format 600 shown inFIG. 6, in which data is transmitted from the Wi-Fi access point 935 tothe Wi-Fi station 945 during a period 910, and then an ACK istransmitted from the Wi-Fi station 945 to the Wi-Fi access point 935during a period 930 following a SIFS 920.

By way of example, FIG. 9 assumes that the Wi-Fi station 945 is a hiddennode with respect to the apparatus 905, and thus, the apparatus 905 maydetect the data transmission during period 910 and determine that theshared radio frequency spectrum band is occupied during a period 940,but may not detect the ACK transmission by the Wi-Fi station 945 duringperiod 930. As a result, when the apparatus 905 successfully completesan ECCA procedure during one of the CCA slots 950 and/or 960, theapparatus 905 may determine that the shared radio frequency spectrumband is available and begin transmitting data that interferes withreception of the ACK transmission by the Wi-Fi access point 935. TheWi-Fi access point's failure to receive or properly decode the ACKtransmission may trigger the start or continuation of an exponentialbackoff by the Wi-Fi access point 935.

One way to decrease the chance that the apparatus 905 will successfullycomplete an ECCA procedure, during the perceived gap in thetransmissions between the Wi-Fi access point 935 and the Wi-Fi station945, is to modify a CCA energy detection threshold for at least one CCAslot in which at least one CCA is performed. For example, the apparatus905 may use a first CCA energy detection threshold to determine whetherthe shared radio frequency spectrum band is available during CCA slotssubsumed in the period 940. Upon determining that the shared radiofrequency spectrum is available, based at least in part on the first CCAenergy detection threshold for a first CCA slot 960, the apparatus 905may sense an energy level of the shared radio frequency spectrum bandduring the first CCA slot 960, and establish a second CCA energydetection threshold (i.e., a dynamic CCA energy detection threshold,wherein the dynamic CCA energy detection threshold may change based atleast in part on the energy levels of transmissions using the sharedradio frequency spectrum band) based at least in part on the sensedenergy level. For example, the sensed energy level may include theenergy level of the ACK transmission during period 930.

The apparatus 905 may perform a number of CCA procedures based at leastin part on the second CCA energy detection threshold. The number of CCAprocedures may be performed in a set of CCA slots (e.g., in a second CCAslot 965, a third CCA slot 970, a fourth CCA slot 975, a fifth CCA slot980, and a sixth CCA slot 985). In some examples, the number of CCAprocedures may include a CCA procedure performed per CCA slot. In someexamples, the number of CCA procedures may include an extended CCAprocedure performed over (or including) the set of CCA slots. Theapparatus 905 may win contention for access to the shared radiofrequency spectrum band when the shared radio frequency spectrum band isdetermined to be available for a subset of CCA slots included in the setof CCA slots (e.g., a subset including one, a plurality of, or all ofthe CCA slots in the set of CCA slots). In some examples, the secondnumber of one or more CCA slots may include a number of consecutive CCAslots, as described with reference to FIG. 8. In some examples, the setof CCA slots may be a single CCA slot (e.g., the second CCA slot 965).After the second CCA energy detection threshold is used for the numberof CCA procedures performed in the set of CCA slots, the CCA energydetection threshold may be restored to the first CCA energy detectionthreshold for performing a subsequent CCA procedure or ECCA procedure.

FIG. 10 shows an exemplary timeline 1000 of CCA slots (e.g., a first CCAslot 1010, a second CCA slot 1015, etc.) in which an ECCA procedure maybe performed by an apparatus 1005 (e.g., a base station (BS) or UE)contending for access to a shared radio frequency spectrum band, inaccordance with various aspects of the present disclosure. The apparatus1005 may be an example of aspects of one or more of the base stations105, 205, 205-a, or 505, or one or more of the UEs 115, 215, 215-a,215-b, or 215-c, described with reference to FIG. 1, 2, or 5. Theapparatus 1005 may also or alternatively be an example of aspects of oneor more of the apparatuses 705, 805, or 905 described with reference toFIG. 7, 8, or 9.

One way to decrease the chance that the apparatus 1005 will successfullycomplete an ECCA procedure, during a perceived gap in transmissionsbetween a Wi-Fi access point and one or more Wi-Fi stations, is toincrease a duration of a last CCA slot 1020 in which an extended CCAprocedure is performed in the CCA slots (e.g., from 20 microseconds to40, 50, or 60 microseconds). In some examples, winning contention foraccess to a shared radio frequency spectrum band may includesuccessfully performing the ECCA procedure (which in FIG. 10 is shown toinclude a determination that the shared radio frequency spectrum band isavailable in N=16 of q=32 CCA slots) and successfully performing theECCA procedure in the last CCA slot 1020 of increased duration. If bothconditions are met (as shown), the apparatus 1005 may win contention foraccess to the shared radio frequency spectrum band during a period 1025following the last CCA slot 1020. If one or the other condition is notmet, the apparatus 1005 may be configured to refrain from accessing theshared radio frequency spectrum band during the period 1025. In someexamples, winning contention for access to the shared radio frequencyspectrum band may require successfully performing an ECCA procedure inthe last CCA slot 1020 and one or more consecutive CCA slots, asdescribed with reference to FIG. 8. In some examples, the duration ofthe last CCA slot 1020 may be increased and its CCA energy detectionthreshold may set to a second CCA energy detection threshold asdescribed with reference to FIG. 9. Such a modification (ormodifications) to an ECCA procedure may be made per cell or per UE, andmay be made by a base station (for one or more UEs) or a UE.

FIG. 11 shows exemplary timelines (e.g., a first timeline 1100, and asecond timeline 1150) of CCA slots (e.g., a first CCA slot 1110, asecond CCA slot 1115, etc.) in which a first ECCA procedure and a secondECCA procedure may be performed by an apparatus 1105 (e.g., a basestation (BS) or UE) contending for access to a shared radio frequencyspectrum band, in accordance with various aspects of the presentdisclosure. The apparatus 1105 may be an example of aspects of one ormore of the base stations 105, 205, 205-a, or 505, or one or more of theUEs 115, 215, 215-a, 215-b, or 215-c, described with reference to FIG.1, 2, or 5. The apparatus 1105 may also or alternatively be an exampleof aspects of one or more of the apparatuses 705, 805, 905, or 1005described with reference to FIG. 7, 8, 9, or 10.

One way to decrease the chance that the apparatus 1105 will successfullycomplete an ECCA procedure, during a perceived gap in transmissionsbetween a Wi-Fi access point and one or more Wi-Fi stations, is toconfigure the apparatus 1105 to successfully perform a plurality of ECCAprocedures before the apparatus 1105 may win contention for access tothe shared radio frequency spectrum band. In some examples, theplurality of ECCA procedures may include a first ECCA procedure followedby a second ECCA procedure. In some examples, the first ECCA proceduremay be performed over a first number of CCA slots and the second ECCAprocedure may be performed over a second number of CCA slots. In someexamples, the second number of CCA slots may be less than the firstnumber of CCA slots. In some examples, the first ECCA procedure and thesecond ECCA procedure may be performed consecutively, or the firstnumber of CCA slots may be contiguous to the second number of CCA slots.

In some examples, successful performance of the first ECCA procedure maybe configured to determine the shared radio frequency spectrum band isavailable for a first random number of CCA slots (e.g., N1 CCA slots),and successful performance of the second ECCA procedure may beconfigured to determine the shared radio frequency spectrum band isavailable for a second random number of CCA slots (e.g., N2 CCA slots).The first random number of CCA slots may be selected from a first rangeof numbers having a first lower bound (q1_(min)) and a first upper bound(q1_(max)), such that N1∈[q1_(min),q1_(max)], and the second randomnumber of CCA slots may be selected from a second range of numbershaving a second lower bound (q2_(min)) and a second upper bound(q2_(max)), such that N2∈[q2_(min),q2_(max)]. In one example, the firstrandom number and the second random number may be selected such thatN1∈[6, 32] and N2∈[1, 5]. When N1 and N2 are selected from overlappingranges of numbers, a limitation may be imposed, in some examples, thatN2 is less than N1. The first timeline 1100 shows an example in whichthe first ECCA procedure is not successful, but the second ECCAprocedure is successful. The second timeline 1150 shows an example inwhich the first ECCA procedure is not successful, and the second ECCAprocedure is not successful. When the second ECCA procedure isunsuccessful, CCA procedures may be performed in a number of additionalCCA slots, and if the CCA procedures are successful in a consecutivenumber of the CCA slots (e.g., N2=5 slots), access to the shared radiofrequency spectrum band may be won.

In some examples, the second ECCA procedure may configured as describedwith reference to FIG. 8, 9, or 10, with a second CCA energy detectionthreshold, a last CCA slot of longer duration, etc.

FIG. 12 shows an exemplary timeline 1200 of communications over a sharedradio frequency spectrum band, between a Wi-Fi access point (AP) 1235and a Wi-Fi station (STA) 1245, as an apparatus 1205 (e.g., a basestation (BS) or UE) contends for access to the shared radio frequencyspectrum band, in accordance with various aspects of the presentdisclosure. The Wi-Fi access point 1235 or the Wi-Fi station 1245 may bean example of aspects of one or more of the Wi-Fi access points 135,535, 735, 835, or 935 or Wi-Fi stations 145, 545, 745, 845, or 945,respectively, as described with reference to FIG. 1, 5, 7, 8, or 9. Theapparatus 1205 may be an example of aspects of one or more of the basestations 105, 205, 205-a, or 505, or one or more of the UEs 115, 215,215-a, 215-b, or 215-c, described with reference to FIG. 1, 2, or 5. Theapparatus 1205 may also or alternatively be an example of aspects of oneor more of the apparatuses 705, 805, 905, 1005, or 1105 described withreference to FIG. 7, 8, 9, 10, or 11.

The communications between the Wi-Fi access point 1235 and the Wi-Fistation 1245 may assume, for example, any of the Wi-Fi transmissionformats shown in FIG. 6, and may switch between uplink transmissions anddownlink transmissions one or more times. By way of example, thecommunications between the Wi-Fi access point 1235 and the Wi-Fi station1245 are shown to assume the first Wi-Fi transmission format shown inFIG. 6, in which data is transmitted from the Wi-Fi access point 1235 tothe Wi-Fi station 1245 during a period 1210, and then an ACK istransmitted from the Wi-Fi station 1245 to the Wi-Fi access point 1235during a period 1230 following a SIFS 1220.

By way of example, FIG. 12 assumes that the Wi-Fi station 1245 is ahidden node with respect to the apparatus 1205, and thus, the apparatus1205 may detect the data transmission during period 1210 and determinethat the shared radio frequency spectrum band is occupied during aperiod 1240, but may not detect the ACK transmission during period 1230.As a result, if the apparatus 1205 successfully completes an ECCAprocedure during the period 1250, the apparatus 1205 may determine thatthe shared radio frequency spectrum band is available and begintransmitting data that interferes with reception of the ACK transmissionby the Wi-Fi access point 1235. The Wi-Fi access point's failure toreceive or properly decode the ACK transmission may trigger the start orcontinuation of an exponential backoff by the Wi-Fi access point 1235.

One way to decrease the chance that the apparatus 1205 will successfullycomplete an ECCA procedure, during the perceived gap in thetransmissions between the Wi-Fi access point 1235 and the Wi-Fi station1245, is to introduce a deferment period 1255 (e.g., an arbitrationinterframe spacing (AIFS)) upon determining the shared radio frequencyspectrum band is unavailable. The deferment period 1255 may be a periodfor which the apparatus 1205 waits before performing an additionalnumber of CCA procedures (which additional number of CCA procedures mayinclude one or more CCA procedures, or which additional number of CCAprocedures may include an additional number of one or more ECCAprocedures). Upon determining the shared radio frequency spectrum bandis available for each of the additional number of CCA procedures, theapparatus 1205 may win contention for access to the shared radiofrequency spectrum band.

In some examples, the deferment period 1255 may be implemented similarlyto a Wi-Fi AIFS and have a duration of a SIFS plus three Wi-Fi slotdurations (e.g., 16+3*9=43 microseconds).

Wi-Fi nodes may use one of two mechanisms to reduce collisions over aWi-Fi network (e.g., over a shared radio frequency spectrum band). Thefirst mechanism is exponential backoff on a per packet basis, and thesecond mechanism is an adaptation of the contention window minimumlength (CW_min) over a period of time. For an apparatus using a sharedradio frequency spectrum band, exponential backoff may not be necessary,due to HARQ combining based on re-transmissions and/or fast channelquality indicator (CQI) adaptations. However, adaptation of the maximumnumber of CCA slots over which an ECCA procedure is performed (e.g., thevalue “q”), over a period of time, may provide better coexistencebetween Wi-Fi nodes and cellular nodes. In some examples, the value of qused by one or more apparatuses may be configured in response to anidentified potential for interference, which potential for interferencemay be identified, for example, based at least in part on one or moreof: a number of transmitters (e.g., a number of Wi-Fi transmitters)detected within an energy detection range of the apparatus; a failurerate of transmissions (e.g., subframes) for which feedback is reported(e.g., by a UE); an erasure rate for transmissions (e.g., subframes) forwhich an error is not reported (e.g., because of bursty interferenceblanking ACKs/NAKs transmitted by a UE); or a variance between asupported modulation and coding scheme (MCS; e.g., an MCS based on adetermined reference signal received power (RSRP)) and an MCS actuallyused (e.g., an MCS based on outer loop HARQ processing).

In some examples, the value of q used by one or more apparatuses may beconfigured by linearly increasing q or linearly decreasing q over time.In some examples, the value of q used by one or more apparatuses may beconfigured by multiplicatively increasing q or linearly decreasing qover time. In some examples, the value of q used by one or moreapparatuses may be configured by multiplicatively increasing q ormultiplicatively decreasing q over time.

FIG. 13 shows an exemplary timeline 1300 of CCA slots (e.g., a first CCAslot 1310, a second CCA slot 1315, a third CCA slot 1320, a fourth CCAslot 1325, etc.) in which an ECCA procedure may be performed by anapparatus 1305 (e.g., a base station or UE) contending for access to ashared radio frequency spectrum band, in accordance with various aspectsof the present disclosure. The apparatus 1305 may be an example ofaspects of one or more of the base stations 105, 205, 205-a, or 505, orone or more of the UEs 115, 215, 215-a, 215-b, 215-c, or 515, describedwith reference to FIG. 1, 2, or 5. The apparatus 1305 may also oralternatively be an example of aspects of one or more of the apparatuses705, 805, 905, 1005, 1105, or 1205 described with reference to FIG. 7,8, 9, 10, 11, or 12.

As shown in a first example of the performance of an ECCA procedure bythe apparatus 1305 (i.e., “App. 1305, Ex. 1”), the ECCA procedure may beperformed over an observation period of q=16 CCA slots, and theapparatus 1305 may win contention for access to the shared radiofrequency spectrum band upon determining the shared radio frequencyspectrum band is available (e.g., idle) for N=9 CCA slots. For purposesof the ECCA procedures shown in FIG. 13, the observation periods overwhich the ECCA procedures are performed may be divided into a pluralityof consecutive, nominal time periods (e.g., consecutive time periods of20 microseconds, including a first time period 1330, a second timeperiod 1335, etc.). An ECCA procedure may then be performed over aplurality of CCA slots (e.g., q=16 CCA slots), where each of the CCAslots may be determined to be an idle slot (I) or an occupied slot (O).An idle CCA slot may correspond to a preconfigured period of time forwhich the shared radio frequency spectrum band is determined to beavailable (e.g., one of the consecutive, nominal time periods). Anoccupied CCA slot may correspond to an entirety of a contiguous periodfor which the shared radio frequency spectrum band is determined to beunavailable (e.g., the three consecutive nominal time periods 1340,1345, and 1350).

Continuing with the description of the first example (App. 1305, Ex. 1),and by way of further example, 13 idle CCA slots and 3 occupied CCAslots may be identified during the performance of the ECCA procedure.Thus, the apparatus 1305 may win contention for access to the sharedradio frequency spectrum band at time 1355 and thereafter reserve oraccess the shared radio frequency spectrum band.

As shown in a second example of the performance of an ECCA procedure bythe apparatus 1305 (i.e., “App. 1305, Ex. 2”), time may be saved bydiscontinuing an ECCA procedure after determining that the shared radiofrequency spectrum band is available for an indicated number of CCAslots. For example, with q=16 and N=9, and the same channel availabilityused in the first example (i.e., in “App. 1305, Ex. 1”), the apparatus1305 may win contention for access to the shared radio frequencyspectrum band at time 1360, earlier than time 1355, and discontinue theECCA procedure. In the second example, the apparatus 1305 may thereforereserve or access the shared radio frequency spectrum band at time 1360,which is earlier than when it could reserve or access the shared radiofrequency spectrum band in the first example.

As shown in a third example of the performance of an ECCA procedure bythe apparatus 1305 (i.e., “App. 1305, Ex. 3”), time may also be saved bydiscontinuing a first ECCA procedure after determining that the sharedradio frequency spectrum band is unavailable during enough CCA slotsthat it is no longer possible to meet a condition that the shared radiofrequency spectrum band be available N CCA slots. For example, with q=16and N=14, and the same channel availability used in the first and secondexamples (i.e., in “App. 1305, Ex. 1” and “App. 1305, Ex. 2”), theapparatus 1305 may determine that it cannot win contention for access tothe shared radio frequency spectrum band at time 1365, earlier than time1355, and discontinue the first ECCA procedure. Upon discontinuing thefirst ECCA procedure, the apparatus 1305 may begin a second ECCAprocedure. The second ECCA procedure may begin immediately after thefirst ECCA procedure terminates, or after a deferment period, or at anext occasion for contending for access to the shared radio frequencyspectrum band. In some examples, the apparatus 1305 may implement anexponential backoff mechanism, such that the second ECCA procedure isperformed in the context of a larger value of q or N. In some examples,the value of q may be doubled for each successive ECCA procedureperformed. In some examples, the value of q may be incremented in alinear or multiplicative manner. Upon winning contention for access tothe shared radio frequency spectrum band, or after a period of time haselapsed, or after the value of q reaches a maximum value (e.g., q=1024),the value of q may be decremented in a linear or multiplicative manner,or the value of q may be reset to an initial value of q (e.g., q=16).

The ECCA procedure(s) described with reference to the second and thirdexamples shown in FIG. 13 (i.e., “App. 1305, Ex. 2” and “App. 1305, Ex.3”) may reduce the chance that different apparatuses contending for theshared radio frequency spectrum band will synchronize with each otherand collide in accessing the shared radio frequency spectrum band. Thesecond and third examples shown in FIG. 13 may also reduce the time toaccess the shared radio frequency spectrum band—especially when q valuesare relatively large and N values are relatively small.

FIG. 14 shows a block diagram 1400 of an apparatus 1405 for use inwireless communication, in accordance with various aspects of thepresent disclosure. The apparatus 1405 may be an example of aspects ofone or more of the base stations 105, 205, 205-a, or 505, or one or moreaspects of the UEs 115, 215, 215-a, 215-b, or 215-c described withreference to FIG. 1, 2, or 5. The apparatus 1405 may also oralternatively be an example of aspects of one or more of the apparatuses705, 805, 905, 1005, 1105, 1205, or 1305 described with reference toFIG. 7, 8, 9, 10, 11, 12, or 13. The apparatus 1405 may also be orinclude a processor. The apparatus 1405 may include a receiver component1410, a wireless communication management component 1420, or atransmitter component 1430. Each of these components may be incommunication with each other.

The components of the apparatus 1405 may, individually or collectively,be implemented using one or more application-specific integratedcircuits (ASICs) adapted to perform some or all of the applicablefunctions in hardware. Alternatively, the functions may be performed byone or more other processing units (or cores), on one or more integratedcircuits. In other examples, other types of integrated circuits may beused (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays(FPGAs), a System on Chip (SoC), or other types of Semi-Custom ICs),which may be programmed in any manner known in the art. The functions ofeach component may also be implemented, in whole or in part, withinstructions embodied in a memory, formatted to be executed by one ormore general or application-specific processors.

In some examples, the receiver component 1410 may include at least oneradio frequency (RF) receiver, such as at least one RF receiver operableto receive transmissions over a dedicated radio frequency spectrum bandor a shared radio frequency spectrum band. The dedicated radio frequencyspectrum band may include a radio frequency spectrum band for whichtransmitting apparatuses may not contend for access (e.g., a radiofrequency spectrum band licensed to particular users for particularuses, such as a licensed radio frequency spectrum band usable forLTE/LTE-A communications). The shared radio frequency spectrum band mayinclude a radio frequency spectrum band for which transmittingapparatuses may need to contend for access (e.g., a radio frequencyspectrum band that is available for unlicensed use, such as Wi-Fi use,or a radio frequency spectrum band that is available for use by multipleoperators in an equally shared or prioritized manner). In some examples,the dedicated radio frequency spectrum band or the shared radiofrequency spectrum band may be used for LTE/LTE-A communications, asdescribed, for example, with reference to FIG. 1 or 2. The receivercomponent 1410 may be used to receive various types of data or controlsignals (i.e., transmissions) over one or more communication links of awireless communication system, such as one or more communication linksof the wireless communication system 100 or 200 described with referenceto FIG. 1 or 2. The communication links may be established over thededicated radio frequency spectrum band or the shared radio frequencyspectrum band.

In some examples, the transmitter component 1430 may include at leastone RF transmitter, such as at least one RF transmitter operable totransmit over the dedicated radio frequency spectrum band or the sharedradio frequency spectrum band. The transmitter component 1430 may beused to transmit various types of data or control signals (i.e.,transmissions) over one or more communication links of a wirelesscommunication system, such as one or more communication links of thewireless communication system 100 or 200 described with reference toFIG. 1 or 2. The communication links may be established over thededicated radio frequency spectrum band or the shared radio frequencyspectrum band.

In some examples, the wireless communication management component 1420may be used to manage one or more aspects of wireless communication forthe apparatus 1405. In some examples, the wireless communicationmanagement component 1420 may include a first RAT communications sensingcomponent 1435 or a second RAT parameter configuration component 1440.

In some examples, the first RAT communications sensing component 1435may be used to sense an indication of first RAT (e.g., Wi-Fi RAT)communications occupying a shared radio frequency spectrum band. Thefirst RAT communications may or may not be a cause of interfere withtransmissions to or from the apparatus 1405 or one or more otherapparatuses.

In some examples, the second RAT parameter configuration component 1440may be used to configure, in response to the sensing, at least oneparameter of a second RAT (e.g., a cellular RAT) used by a device tocontend for access to the shared radio frequency spectrum band. Thedevice may be the apparatus 1405 or another apparatus. For example, whenthe apparatus 1405 is a base station, the device for which the at leastone parameter of the second RAT is configured may be the apparatus 1405,a single UE, or a plurality of UEs (e.g., all of the UEs of a cell inwhich the apparatus 1405 operates). When the apparatus 1405 is a UE, thedevice for which the at least one parameter of the second RAT isconfigured may be the apparatus 1405.

FIG. 15 shows a block diagram 1500 of an apparatus 1505 for use inwireless communication, in accordance with various aspects of thepresent disclosure. The apparatus 1505 may be an example of aspects ofone or more of the base stations 105, 205, 205-a, or 505, or one or moreaspects of the UEs 115, 215, 215-a, 215-b, or 215-c described withreference to FIG. 1, 2, or 5. The apparatus 1505 may also oralternatively be an example of aspects of one or more of the apparatuses705, 805, 905, 1005, 1105, 1205, 1305, or 1405 described with referenceto FIG. 7, 8, 9, 10, 11, 12, 13, or 14. The apparatus 1505 may also beor include a processor. The apparatus 1505 may include a receivercomponent 1510, a wireless communication management component 1520, or atransmitter component 1530. Each of these components may be incommunication with each other.

The components of the apparatus 1505 may, individually or collectively,be implemented using one or more ASICs adapted to perform some or all ofthe applicable functions in hardware. Alternatively, the functions maybe performed by one or more other processing units (or cores), on one ormore integrated circuits. In other examples, other types of integratedcircuits may be used (e.g., Structured/Platform ASICs, FPGAs, a SoC, orother types of Semi-Custom ICs), which may be programmed in any mannerknown in the art. The functions of each component may also beimplemented, in whole or in part, with instructions embodied in amemory, formatted to be executed by one or more general orapplication-specific processors.

In some examples, the receiver component 1510 may include at least oneRF receiver, such as at least one RF receiver operable to receivetransmissions over a dedicated radio frequency spectrum band or a sharedradio frequency spectrum band. The dedicated radio frequency spectrumband may include a radio frequency spectrum band for which transmittingapparatuses may not contend for access (e.g., a radio frequency spectrumband licensed to particular users for particular uses, such as alicensed radio frequency spectrum band usable for LTE/LTE-Acommunications). The shared radio frequency spectrum band may include aradio frequency spectrum band for which transmitting apparatuses mayneed to contend for access (e.g., a radio frequency spectrum band thatis available for unlicensed use, such as Wi-Fi use, or a radio frequencyspectrum band that is available for use by multiple operators in anequally shared or prioritized manner). In some examples, the dedicatedradio frequency spectrum band or the shared radio frequency spectrumband may be used for LTE/LTE-A communications, as described, forexample, with reference to FIG. 1 or 2. The receiver component 1510 mayin some cases include separate receivers for the dedicated radiofrequency spectrum band and the shared radio frequency spectrum band.The separate receivers may, in some examples, take the form of anLTE/LTE-A receiver component for communicating over the dedicated radiofrequency spectrum band (e.g., LTE/LTE-A receiver component fordedicated RF spectrum band 1512), and an LTE/LTE-A receiver componentfor communicating over the shared radio frequency spectrum band (e.g.,LTE/LTE-A receiver component for shared RF spectrum band 1514). Thereceiver component 1510, including the LTE/LTE-A receiver component fordedicated RF spectrum band 1512 or the LTE/LTE-A receiver component forshared RF spectrum band 1514, may be used to receive various types ofdata or control signals (i.e., transmissions) over one or morecommunication links of a wireless communication system, such as one ormore communication links of the wireless communication system 100 or 200described with reference to FIG. 1 or 2. The communication links may beestablished over the dedicated radio frequency spectrum band or theshared radio frequency spectrum band.

In some examples, the transmitter component 1530 may include at leastone RF transmitter, such as at least one RF transmitter operable totransmit over the dedicated radio frequency spectrum band or the sharedradio frequency spectrum band. The transmitter component 1530 may insome cases include separate transmitters for the dedicated radiofrequency spectrum band and the shared radio frequency spectrum band.The separate transmitters may, in some examples, take the form of anLTE/LTE-A transmitter component for communicating over the dedicatedradio frequency spectrum band (e.g., LTE/LTE-A transmitter component fordedicated RF spectrum band 1532), and an LTE/LTE-A transmitter componentfor communicating over the shared radio frequency spectrum band (e.g.,LTE/LTE-A transmitter component for shared RF spectrum band 1534). Thetransmitter component 1530, including the LTE/LTE-A transmittercomponent for dedicated RF spectrum band 1532 or the LTE/LTE-Atransmitter component for shared RF spectrum band 1534, may be used totransmit various types of data or control signals (i.e., transmissions)over one or more communication links of a wireless communication system,such as one or more communication links of the wireless communicationsystem 100 or 200 described with reference to FIG. 1 or 2. Thecommunication links may be established over the first radio frequencyspectrum band or the second radio frequency spectrum band.

In some examples, the wireless communication management component 1520may be used to manage one or more aspects of wireless communication forthe apparatus 1505. In some examples, the wireless communicationmanagement component 1520 may include a first RAT communications sensingcomponent 1535 or a second RAT parameter configuration component 1540.

In some examples, the first RAT communications sensing component 1535may be used to sense an indication of first RAT (e.g., Wi-Fi RAT)communications occupying a shared radio frequency spectrum band. In someexamples, the first RAT communications sensing component 1535 mayinclude a transmitter detection component 1545, a transmission failureidentification component 1550, an erasure rate identification component1555, or an MCS variation detection component 1560. The transmitterdetection component 1545 may be used to detect a number of transmitters(e.g., a number of Wi-Fi transmitters) within an energy detection rangeof a device (e.g., within range of the apparatus 1505 or one or moreother apparatuses). The transmission failure identification component1550 may be used to determine a failure rate of transmissions (e.g.,subframes) for which feedback is reported (e.g., by the apparatus 1505or by one or more other apparatuses). The erasure rate identificationcomponent 1555 may be used to determine an erasure rate fortransmissions (e.g., subframes) for which an error is not reported(e.g., because of bursty interference blanking ACKs/NAKs transmitted bythe apparatus 1505 or one or more other apparatuses). The MCS variationdetection component 1560 may be used to detect a variance between 1) asupported modulation and coding scheme (MCS; e.g., an MCS based on adetermined reference signal received power (RSRP)) for the apparatus1505 or one or more other apparatuses, and 2) an MCS actually used bythe apparatus 1505 or one or more other apparatuses (e.g., an MCS basedon outer loop HARQ processing). In some examples, the first RATcommunications sensing component 1535 may sense the indication of firstRAT communications based at least in part on detections ordeterminations made by one or more of the transmitter detectioncomponent 1545, the transmission failure identification component 1550,the erasure rate identification component 1555, or the MCS variationdetection component 1560.

In some examples, the second RAT parameter configuration component 1540may be used to configure, in response to the sensing, at least oneparameter of a second RAT (e.g., a cellular RAT) used by a device tocontend for access to the shared radio frequency spectrum band. Thedevice may be the apparatus 1505 or another apparatus. For example, whenthe apparatus 1505 is a base station, the device for which the at leastone parameter of the second RAT is configured may be the apparatus 1505,a single UE, or a plurality of UEs (e.g., all of the UEs of a cell inwhich the apparatus 1505 operates). When the apparatus 1505 is a UE, thedevice for which the at least one parameter of the second RAT isconfigured may be the apparatus 1505.

In some examples, the second RAT parameter configuration component 1540may include an ECCA configuration component 1565, a consecutive CCA slotconfiguration component 1570, a CCA energy detection thresholdconfiguration component 1575, a CCA slot duration configurationcomponent 1580, an ECCA number configuration component 1585, or aCCA/ECCA deferment period configuration component 1590.

In some examples, the ECCA configuration component 1565 may be used toconfigure an ECCA procedure for the device, and may include an ECCArange configuration component 1595. The ECCA range configurationcomponent 1595 may be used, in some examples, to configure a range ofnumbers from which a random number may be selected. The random numbermay determine a number of CCA slots over which the device performs anECCA procedure. In some examples, the range of numbers may be configuredby at least one of: increasing a lower bound of the range of numbers, orincreasing an upper bound of the range of numbers, or a combinationthereof.

In some examples, the ECCA range configuration component 1595 may alsoor alternatively be used to configure a maximum number of CCA slots overwhich an extended CCA procedure is performed by linearly increasing themaximum number of CCA slots or linearly decreasing the maximum number ofCCA slots. In some examples, the ECCA range configuration component 1595may be used to configure a maximum number of CCA slots over which anECCA procedure is performed by multiplicatively increasing the number ofCCA slots or linearly decreasing the number of CCA slots. In someexamples, the ECCA range configuration component 1595 may be used toconfigure a maximum number of CCA slots over which an ECCA procedure isperformed by multiplicatively increasing the number of CCA slots ormultiplicatively decreasing the number of CCA slots.

In some examples, the consecutive CCA slot configuration component 1570may be used to identify a number of consecutive CCA slots for which theshared radio frequency spectrum band is available before the device winscontention for access to the shared radio frequency spectrum band. Whenthe device has not won contention for access to the shared radiofrequency spectrum band, the identified number of CCA slots may be alast number of CCA slots in which an ECCA procedure is performed.Alternatively, when the device has not won contention for access to theshared radio frequency spectrum band, the identified number of CCA slotsmay include at least one of: a last number of CCA slots in which an ECCAprocedure is performed, or a number of CCA slots in which the ECCAprocedure is performed in combination with at least one CCA slotfollowing a last CCA slot in which the ECCA procedure is performed. Whenthe device has won contention for access to the shared radio frequencyspectrum band and is in an idle state with respect to the shared radiofrequency spectrum band, the specified number of CCA slots may includeCCA slots in which CCA procedures are to be performed.

In some examples, the CCA energy detection threshold configurationcomponent 1575 may be used to configure a first CCA energy detectionthreshold (e.g., a default CCA energy detection threshold) or a secondCCA energy detection threshold (e.g., a dynamic CCA energy detectionthreshold). The CCA energy detection threshold configuration component1575 may configure the second CCA energy detection threshold for atleast one CCA slot in which at least one CCA procedure is performed.Also or alternatively, the CCA energy detection threshold configurationcomponent 1575 may be used to configure the device to sense an energylevel of the shared radio frequency spectrum band following a period inwhich the shared radio frequency spectrum band is occupied, and toconfigure the second CCA energy detection threshold based at least inpart on the sensed energy. The CCA energy detection thresholdconfiguration component 1575 may also be used to configure the device toperform a number of CCA procedures based at least in part on the secondCCA energy detection threshold, in a set of CCA slots, and to configurethe device to win contention for access to the shared radio frequencyspectrum band when the shared radio frequency spectrum band isdetermined to be available for a subset of CCA slots included in the setof CCA slots (e.g., a subset including one, a plurality of, or all ofthe CCA slots in the set of CCA slots). In some examples, the secondnumber of CCA slots may be a number of consecutive CCA slots.

In some examples, the CCA slot duration configuration component 1580 maybe used to increase a duration of a last CCA slot in which an ECCAprocedure is performed. In some examples, the CCA slot durationconfiguration component 1580 may cause the CCA energy detectionthreshold configuration component 1575 to also configure the second CCAenergy detection threshold for the last CCA slot in which the ECCAprocedure is performed.

In some examples, the ECCA number configuration component 1585 may beused to configure the device to perform a plurality of ECCA proceduresto contend for access to the shared radio frequency spectrum band. Insome examples, the plurality of ECCA procedures may include a first ECCAprocedure followed by a second ECCA procedure. In some examples, thefirst ECCA procedure may be configured to be performed over a firstnumber of CCA slots and the second ECCA procedure may be configured tobe performed over a second number of CCA slots. The second number may beless than the first number. In some examples, the ECCA numberconfiguration component 1585 may cause the consecutive CCA slotconfiguration component 1570 to configure the device to identify anumber of consecutive CCA slots for which the shared radio frequencyspectrum band is available, during or after the second ECCA, before thedevice wins contention for access to the shared radio frequency spectrumband.

In some examples, the CCA/ECCA deferment period configuration component1590 may be used to configure a deferment period for the device. Thedeferment period may cause the device to wait for the deferment period,upon determining the shared radio frequency spectrum band isunavailable, before performing an additional number of CCA procedures(which in some cases may include a number of ECCA procedures).

FIG. 16 shows a block diagram 1600 of an apparatus 1605 for use inwireless communication, in accordance with various aspects of thepresent disclosure. The apparatus 1605 may be an example of aspects ofone or more of the base stations 105, 205, 205-a, or 505, or one or moreaspects of the UEs 115, 215, 215-a, 215-b, or 215-c described withreference to FIG. 1, 2, or 5. The apparatus 1605 may also oralternatively be an example of aspects of one or more of the apparatuses705, 805, 905, 1005, 1105, 1205, 1305, 1405, or 1505 described withreference to FIG. 7, 8, 9, 10, 11, 12, 13, 14, or 15. The apparatus 1605may also be or include a processor. The apparatus 1605 may include areceiver component 1610, a wireless communication management component1620, or a transmitter component 1630. Each of these components may bein communication with each other.

The components of the apparatus 1605 may, individually or collectively,be implemented using one or more ASICs adapted to perform some or all ofthe applicable functions in hardware. Alternatively, the functions maybe performed by one or more other processing units (or cores), on one ormore integrated circuits. In other examples, other types of integratedcircuits may be used (e.g., Structured/Platform ASICs, FPGAs, a SoC, orother types of Semi-Custom ICs), which may be programmed in any mannerknown in the art. The functions of each component may also beimplemented, in whole or in part, with instructions embodied in amemory, formatted to be executed by one or more general orapplication-specific processors.

In some examples, the receiver component 1610 may include at least oneradio frequency (RF) receiver, such as at least one RF receiver operableto receive transmissions over a dedicated radio frequency spectrum bandor a shared radio frequency spectrum band. The dedicated radio frequencyspectrum band may include a radio frequency spectrum band for whichtransmitting apparatuses may not contend for access (e.g., a radiofrequency spectrum band licensed to particular users for particularuses, such as a licensed radio frequency spectrum band usable forLTE/LTE-A communications). The shared radio frequency spectrum band mayinclude a radio frequency spectrum band for which transmittingapparatuses may need to contend for access (e.g., a radio frequencyspectrum band that is available for unlicensed use, such as Wi-Fi use,or a radio frequency spectrum band that is available for use by multipleoperators in an equally shared or prioritized manner). In some examples,the dedicated radio frequency spectrum band or the shared radiofrequency spectrum band may be used for LTE/LTE-A communications, asdescribed, for example, with reference to FIG. 1 or 2. The receivercomponent 1610 may be used to receive various types of data or controlsignals (i.e., transmissions) over one or more communication links of awireless communication system, such as one or more communication linksof the wireless communication system 100 or 200 described with referenceto FIG. 1 or 2. The communication links may be established over thededicated radio frequency spectrum band or the shared radio frequencyspectrum band.

In some examples, the transmitter component 1630 may include at leastone RF transmitter, such as at least one RF transmitter operable totransmit over the dedicated radio frequency spectrum band or the sharedradio frequency spectrum band. The transmitter component 1630 may beused to transmit various types of data or control signals (i.e.,transmissions) over one or more communication links of a wirelesscommunication system, such as one or more communication links of thewireless communication system 100 or 200 described with reference toFIG. 1 or 2. The communication links may be established over thededicated radio frequency spectrum band or the shared radio frequencyspectrum band.

In some examples, the wireless communication management component 1620may be used to manage one or more aspects of wireless communication forthe apparatus 1605. In some examples, the wireless communicationmanagement component 1620 may include an ECCA procedure configurationcomponent 1635 or an ECCA procedure performance component 1640.

In some examples, the ECCA procedure configuration component 1635 may beused to configure an ECCA procedure. In some examples, configuring theECCA procedure may include randomly selecting a number from a range ofnumbers extending between a lower bound and an upper bound. The numbermay determine how many CCA slots a shared radio frequency spectrum bandmust be determined “available,” during the performance of an ECCAprocedure, before an apparatus performing the ECCA procedure can wincontention for access to the shared radio frequency spectrum band.

In some examples, the ECCA procedure performance component 1640 may beused to perform the configured ECCA procedure. Performing the ECCAprocedure may include contending for access to a shared radio frequencyspectrum band by performing the ECCA procedure over a plurality of CCAslots. The plurality of CCA slots may include a first number of CCAslots equal to the upper bound of the range of numbers. The ECCAprocedure performance component 1640 may determine that contention foraccess to the shared radio frequency spectrum band has been won afterdetermining, while the ECCA procedure is being performed, that theshared radio frequency spectrum band is available for a second number ofCCA slots equal to the randomly selected number. In some examples, theECCA procedure performance component 1640 may include a successful ECCAdiscontinuation component 1645. The successful ECCA discontinuationcomponent 1645 may discontinue the ECCA procedure upon determining thatcontention for access to the shared radio frequency spectrum band hasbeen won.

In some examples, each of the CCA slots over which the ECCA procedure isperformed may include a preconfigured period of time for which theshared radio frequency spectrum band is available, or an entirety of acontiguous period for which the shared radio frequency spectrum band isunavailable. In other examples, each of the CCA slots over which theECCA procedure is performed may include a preconfigured period of time.

FIG. 17 shows a block diagram 1700 of an apparatus 1705 for use inwireless communication, in accordance with various aspects of thepresent disclosure. The apparatus 1705 may be an example of aspects ofone or more of the base stations 105, 205, 205-a, or 505, or one or moreaspects of the UEs 115, 215, 215-a, 215-b, or 215-c described withreference to FIG. 1, 2, or 5. The apparatus 1705 may also oralternatively be an example of aspects of one or more of the apparatuses705, 805, 905, 1005, 1105, 1205, 1305, 1405, 1505, or 1605 describedwith reference to FIG. 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16. Theapparatus 1705 may also be or include a processor. The apparatus 1705may include a receiver component 1710, a wireless communicationmanagement component 1720, or a transmitter component 1730. Each ofthese components may be in communication with each other.

The components of the apparatus 1705 may, individually or collectively,be implemented using one or more ASICs adapted to perform some or all ofthe applicable functions in hardware. Alternatively, the functions maybe performed by one or more other processing units (or cores), on one ormore integrated circuits. In other examples, other types of integratedcircuits may be used (e.g., Structured/Platform ASICs, FPGAs, a SoC, orother types of Semi-Custom ICs), which may be programmed in any mannerknown in the art. The functions of each component may also beimplemented, in whole or in part, with instructions embodied in amemory, formatted to be executed by one or more general orapplication-specific processors.

In some examples, the receiver component 1710 may include at least oneRF receiver, such as at least one RF receiver operable to receivetransmissions over a dedicated radio frequency spectrum band or a sharedradio frequency spectrum band. The dedicated radio frequency spectrumband may include a radio frequency spectrum band for which transmittingapparatuses may not contend for access (e.g., a radio frequency spectrumband licensed to particular users for particular uses, such as alicensed radio frequency spectrum band usable for LTE/LTE-Acommunications). The shared radio frequency spectrum band may include aradio frequency spectrum band for which transmitting apparatuses mayneed to contend for access (e.g., a radio frequency spectrum band thatis available for unlicensed use, such as Wi-Fi use, or a radio frequencyspectrum band that is available for use by multiple operators in anequally shared or prioritized manner). In some examples, the dedicatedradio frequency spectrum band or the shared radio frequency spectrumband may be used for LTE/LTE-A communications, as described, forexample, with reference to FIG. 1 or 2. The receiver component 1710 mayin some cases include separate receivers for the dedicated radiofrequency spectrum band and the shared radio frequency spectrum band.The separate receivers may, in some examples, take the form of anLTE/LTE-A receiver component for communicating over the dedicated radiofrequency spectrum band (e.g., LTE/LTE-A receiver component fordedicated RF spectrum band 1712), and an LTE/LTE-A receiver componentfor communicating over the shared radio frequency spectrum band (e.g.,LTE/LTE-A receiver component for shared RF spectrum band 1714). Thereceiver component 1710, including the LTE/LTE-A receiver component fordedicated RF spectrum band 1712 or the LTE/LTE-A receiver component forshared RF spectrum band 1714, may be used to receive various types ofdata or control signals (i.e., transmissions) over one or morecommunication links of a wireless communication system, such as one ormore communication links of the wireless communication system 100 or 200described with reference to FIG. 1 or 2. The communication links may beestablished over the dedicated radio frequency spectrum band or theshared radio frequency spectrum band.

In some examples, the transmitter component 1730 may include at leastone RF transmitter, such as at least one RF transmitter operable totransmit over the dedicated radio frequency spectrum band or the sharedradio frequency spectrum band. The transmitter component 1730 may insome cases include separate transmitters for the dedicated radiofrequency spectrum band and the shared radio frequency spectrum band.The separate transmitters may, in some examples, take the form of anLTE/LTE-A transmitter component for communicating over the dedicatedradio frequency spectrum band (e.g., LTE/LTE-A transmitter component fordedicated RF spectrum band 1732), and an LTE/LTE-A transmitter componentfor communicating over the shared radio frequency spectrum band (e.g.,LTE/LTE-A transmitter component for shared RF spectrum band 1734). Thetransmitter component 1730, including the LTE/LTE-A transmittercomponent for dedicated RF spectrum band 1732 or the LTE/LTE-Atransmitter component for shared RF spectrum band 1734, may be used totransmit various types of data or control signals (i.e., transmissions)over one or more communication links of a wireless communication system,such as one or more communication links of the wireless communicationsystem 100 or 200 described with reference to FIG. 1 or 2. Thecommunication links may be established over the first radio frequencyspectrum band or the second radio frequency spectrum band.

In some examples, the wireless communication management component 1720may be used to manage one or more aspects of wireless communication forthe apparatus 1705. In some examples, the wireless communicationmanagement component 1720 may include an ECCA procedure configurationcomponent 1735 or an ECCA procedure performance component 1740.

In some examples, the ECCA procedure configuration component 1735 may beused to configure an ECCA procedure. In some examples, configuring theECCA procedure may include randomly selecting a number from a range ofnumbers extending between a lower bound and an upper bound. The numbermay determine how many CCA slots a shared radio frequency spectrum bandmust be determined “available,” during the performance of an ECCAprocedure, before an apparatus performing the ECCA procedure can wincontention for access to the shared radio frequency spectrum band.

In some examples, the ECCA procedure performance component 1740 may beused to perform the configured ECCA procedure. Performing the ECCAprocedure may include contending for access to a shared radio frequencyspectrum band by performing the ECCA procedure over a plurality of CCAslots. The plurality of CCA slots may include a first number of CCAslots equal to the upper bound of the range of numbers. The ECCAprocedure performance component 1740 may determine that contention foraccess to the shared radio frequency spectrum band has been won afterdetermining, while the ECCA procedure is being performed, that theshared radio frequency spectrum band is available for a second number ofCCA slots equal to the randomly selected number. The ECCA procedureperformance component 1740 may also determine that contention for accessto the shared radio frequency spectrum band has failed afterdetermining, while the ECCA procedure is being performed, that theshared radio frequency spectrum band is unavailable for a third numberof CCA slots equal to the first number of CCA slots, less the randomlyselected number, plus one. In some examples, the ECCA procedureperformance component 1740 may include a successful ECCA discontinuationcomponent 1745 or an unsuccessful ECCA discontinuation component 1750.The successful ECCA discontinuation component 1745 may discontinue theECCA procedure upon determining that contention for access to the sharedradio frequency spectrum band has been won. The unsuccessful ECCAdiscontinuation component 1750 may discontinue the ECCA procedure upondetermining that contention for access to the shared radio frequencyspectrum band has failed.

In some examples, each of the CCA slots over which the ECCA procedure isperformed may include a preconfigured period of time for which theshared radio frequency spectrum band is available, or an entirety of acontiguous period for which the shared radio frequency spectrum band isunavailable. In other examples, each of the CCA slots over which theECCA procedure is performed may include a preconfigured period of time.

FIG. 18 shows a block diagram 1800 of a base station 1805 (e.g., a basestation forming part or all of an eNB) for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure. In some examples, the base station 1805 may be an example ofone or more aspects of the base station 105, 205, 205-a, or 505described with reference to FIG. 1, 2, or 5, or aspects of one or moreof the apparatuses 705, 805, 905, 1005, 1105, 1205, 1305, 1405, 1505, or1605 described with reference to FIG. 7, 8, 9, 10, 11, 12, 13, 14, 15,16, or 17. The base station 1805 may be configured to implement orfacilitate at least some of the base station features and functionsdescribed with reference to FIG. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, 14, 15, 16, or 17.

The base station 1805 may include a base station processor component1810, a base station memory component 1820, at least one base stationtransceiver component (represented by base station transceivercomponent(s) 1850), at least one base station antenna (represented bybase station antenna(s) 1855), or a base station wireless communicationmanagement component 1860. The base station 1805 may also include one ormore of a base station communications component 1830 or a networkcommunications component 1840. Each of these components may be incommunication with each other, directly or indirectly, over one or morebuses 1835.

The base station memory component 1820 may include random access memory(RAM) or read-only memory (ROM). The base station memory component 1820may store computer-readable, computer-executable code 1825 containinginstructions that are configured to, when executed, cause the basestation processor component 1810 to perform various functions describedherein related to sensing an indication of first RAT (e.g., a Wi-Fi RAT)communications; configuring, in response to the sensing, at least oneparameter of a second RAT (e.g., a cellular RAT) used by a device (e.g.,the base station 1805 or one or more UEs) to contend for access to ashared radio frequency spectrum band; or contending for access to theshared radio frequency spectrum band. Alternatively, the code 1825 maynot be directly executable by the base station processor component 1810but be configured to cause the base station 1805 (e.g., when compiledand executed) to perform various of the functions described herein.

The base station processor component 1810 may include an intelligenthardware device, e.g., a central processing unit (CPU), amicrocontroller, an ASIC, etc. The base station processor component 1810may process information received through the base station transceivercomponent(s) 1850, the base station communications component 1830, orthe network communications component 1840. The base station processorcomponent 1810 may also process information to be sent to thetransceiver component(s) 1850 for transmission through the antenna(s)1855, to the base station communications component 1830, fortransmission to one or more other base stations 1805-a and 1805-b, or tothe network communications component 1840 for transmission to a corenetwork 1845, which may be an example of one or more aspects of the corenetwork 130 described with reference to FIG. 1. The base stationprocessor component 1810 may handle, alone or in connection with thebase station wireless communication management component 1860, variousaspects of communicating over (or managing communications over) adedicated radio frequency spectrum band or the shared radio frequencyspectrum band. The dedicated radio frequency spectrum band may include aradio frequency spectrum band for which transmitting apparatuses may notcontend for access (e.g., a radio frequency spectrum band licensed toparticular users for particular uses, such as a licensed radio frequencyspectrum band usable for LTE/LTE-A communications). The shared radiofrequency spectrum band may include a radio frequency spectrum band forwhich transmitting apparatuses may need to contend for access (e.g., aradio frequency spectrum band that is available for unlicensed use, suchas Wi-Fi use, or a radio frequency spectrum band that is available foruse by multiple operators in an equally shared or prioritized manner).

The base station transceiver component(s) 1850 may include a modemconfigured to modulate packets and provide the modulated packets to thebase station antenna(s) 1855 for transmission, and to demodulate packetsreceived from the base station antenna(s) 1855. The base stationtransceiver component(s) 1850 may, in some examples, be implemented asone or more base station transmitter components and one or more separatebase station receiver components. The base station transceivercomponent(s) 1850 may support communications in the dedicated radiofrequency spectrum band or the shared radio frequency spectrum band. Thebase station transceiver component(s) 1850 may be configured tocommunicate bi-directionally, via the antenna(s) 1855, with one or moreUEs or apparatuses, such as one or more of the UEs 115, 215, 215-a,215-b, or 215-c described with reference to FIG. 1, 2, or 5. The basestation 1805 may, for example, include multiple base station antennas1855 (e.g., an antenna array). The base station 1805 may communicatewith the core network 1845 through the network communications component1840. The base station 1805 may also communicate with other basestations, such as the base stations 1805-a and 1805-b, using the basestation communications component 1830.

The base station wireless communication management component 1860 may beconfigured to perform or control some or all of the features orfunctions described with reference to FIG. 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, or 18 related to wireless communicationover the dedicated radio frequency spectrum band or the shared radiofrequency spectrum band. For example, the base station wirelesscommunication management component 1860 may be configured to support asupplemental downlink mode (e.g., a licensed assisted access mode), acarrier aggregation mode, or a standalone mode using the dedicated radiofrequency spectrum band or the shared radio frequency spectrum band. Thebase station wireless communication management component 1860 mayinclude a base station LTE/LTE-A component for dedicated RF spectrumband 1865 configured to handle LTE/LTE-A communications in the dedicatedradio frequency spectrum band, and a base station LTE/LTE-A componentfor shared RF spectrum band 1870 configured to handle LTE/LTE-Acommunications in the shared radio frequency spectrum band. The basestation wireless communication management component 1860, or portions ofit, may include a processor, or some or all of the functions of the basestation wireless communication management component 1860 may beperformed by the base station processor component 1810 or in connectionwith the base station processor component 1810. In some examples, thebase station wireless communication management component 1860 may be anexample of the wireless communication management component 1420, 1520,1620, or 1720 described with reference to FIG. 14, 15, 16, or 17.

FIG. 19 shows a block diagram 1900 of a UE 1915 for use in wirelesscommunication, in accordance with various aspects of the presentdisclosure. The UE 1915 may have various configurations and may beincluded or be part of a personal computer (e.g., a laptop computer, anetbook computer, a tablet computer, etc.), a cellular telephone, a PDA,a digital video recorder (DVR), an internet appliance, a gaming console,an e-reader, etc. The UE 1915 may, in some examples, have an internalpower supply (not shown), such as a small battery, to facilitate mobileoperation. In some examples, the UE 1915 may be an example of aspects ofone or more of the UEs 115, 215, 215-a, 215-b, or 215-c described withreference to FIG. 1 or 2, or aspects of one or more of the apparatuses705, 805, 905, 1005, 1105, 1205, 1305, 1405, 1505, 1605, or 1705described with reference to FIG. 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or17. The UE 1915 may be configured to implement at least some of the UEor apparatus features and functions described with reference to FIG. 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17.

The UE 1915 may include a UE processor component 1910, a UE memorycomponent 1920, at least one UE transceiver component (represented by UEtransceiver component(s) 1930), at least one UE antenna (represented byUE antenna(s) 1940), or a UE wireless communication management component1960. Each of these components may be in communication with each other,directly or indirectly, over one or more buses 1935.

The UE memory component 1920 may include RAM or ROM. The UE memorycomponent 1920 may store computer-readable, computer-executable code1925 containing instructions that are configured to, when executed,cause the UE processor component 1910 to perform various functionsdescribed herein related to sensing an indication of first RAT (e.g., aWi-Fi RAT) communications; configuring, in response to the sensing, atleast one parameter of a second RAT (e.g., a cellular RAT) used by adevice (e.g., the UE 1915) to contend for access to a shared radiofrequency spectrum band; or contending for access to the shared radiofrequency spectrum band.

The UE processor component 1910 may include an intelligent hardwaredevice, e.g., a CPU, a microcontroller, an ASIC, etc. The UE processorcomponent 1910 may process information received through the UEtransceiver component(s) 1930 or information to be sent to the UEtransceiver component(s) 1930 for transmission through the UE antenna(s)1940. The UE processor component 1910 may handle, alone or in connectionwith the UE wireless communication management component 1960, variousaspects of communicating over (or managing communications over) adedicated radio frequency spectrum band or the shared radio frequencyspectrum band. The dedicated radio frequency spectrum band may include aradio frequency spectrum band for which transmitting apparatuses may notcontend for access (e.g., a radio frequency spectrum band licensed toparticular users for particular uses, such as a licensed radio frequencyspectrum band usable for LTE/LTE-A communications). The shared radiofrequency spectrum band may include a radio frequency spectrum band forwhich transmitting apparatuses may need to contend for access (e.g., aradio frequency spectrum band that is available for unlicensed use, suchas Wi-Fi use, or a radio frequency spectrum band that is available foruse by multiple operators in an equally shared or prioritized manner).

The UE transceiver component(s) 1930 may include a modem configured tomodulate packets and provide the modulated packets to the UE antenna(s)1940 for transmission, and to demodulate packets received from the UEantenna(s) 1940. The UE transceiver component(s) 1930 may, in someexamples, be implemented as one or more UE transmitter components andone or more separate UE receiver components. The UE transceivercomponent(s) 1930 may support communications in the licensed radiofrequency spectrum band or the unlicensed radio frequency spectrum band.The UE transceiver component(s) 1930 may be configured to communicatebi-directionally, via the UE antenna(s) 1940, with one or more of thebase stations 105, 205, 205-a, 505, or 1805 described with reference toFIG. 1, 2, 5, or 18. While the UE 1915 may include a single UE antenna,there may be examples in which the UE 1915 may include multiple UEantennas 1940.

The UE state component 1950 may be used, for example, to managetransitions of the UE 1915 between an RRC idle state and an RRCconnected state, and may be in communication with other components ofthe UE 1915, directly or indirectly, over the one or more buses 1935.The UE state component 1950, or portions of it, may include a processor,or some or all of the functions of the UE state component 1950 may beperformed by the UE processor component 1910 or in connection with theUE processor component 1910.

The UE wireless communication management component 1960 may beconfigured to perform or control some or all of the UE or apparatusfeatures or functions described with reference to FIG. 1, 2, 3, 4, 5, 6,7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 related to wirelesscommunication over the dedicated radio frequency spectrum band or theshared radio frequency spectrum band. For example, the UE wirelesscommunication management component 1960 may be configured to support asupplemental downlink mode (e.g., a licensed assisted access mode), acarrier aggregation mode, or a standalone mode using the dedicated radiofrequency spectrum band or the shared radio frequency spectrum band. TheUE wireless communication management component 1960 may include a UELTE/LTE-A component for dedicated RF spectrum band 1965 configured tohandle LTE/LTE-A communications in the dedicated radio frequencyspectrum band, and a UE LTE/LTE-A component for shared RF spectrum band1970 configured to handle LTE/LTE-A communications in the shared radiofrequency spectrum band. The UE wireless communication managementcomponent 1960, or portions of it, may include a processor, or some orall of the functions of the UE wireless communication managementcomponent 1960 may be performed by the UE processor component 1910 or inconnection with the UE processor component 1910. In some examples, theUE wireless communication management component 1960 may be an example ofthe wireless communication management component 1420, 1520, 1620, or1720 described with reference to FIG. 14, 15, 16, or 17.

FIG. 20 is a flow chart illustrating an exemplary method 2000 forwireless communication, in accordance with various aspects of thepresent disclosure. For clarity, the method 2000 is described below withreference to aspects of one or more of the base stations 105, 205,205-a, 505, or 1805 described with reference to FIG. 1, 2, 5, or 18,aspects of one or more of the UEs 115, 215, 215-a, 215-b, 215-c, or 1915described with reference to FIG. 1, 2, or 19, or aspects of one or moreof the apparatuses 705, 805, 905, 1005, 1105, 1205, 1305, 1405, 1505,1605, or 1705 described with reference to FIG. 7, 8, 9, 10, 11, 12, 13,14, 15, 16, or 17. In some examples, a base station, UE, or apparatusmay execute one or more sets of codes to control the functional elementsof the base station, UE, or apparatus to perform the functions describedbelow. Additionally or alternatively, the base station, UE, or apparatusmay perform one or more of the functions described below usingspecial-purpose hardware.

At block 2005, the method 2000 may include sensing an indication offirst RAT (e.g., a Wi-Fi RAT) communications occupying a shared radiofrequency spectrum band. The shared radio frequency spectrum band mayinclude a radio frequency spectrum band for which transmittingapparatuses may need to contend for access (e.g., a radio frequencyspectrum band that is available for unlicensed use, such as Wi-Fi use,or a radio frequency spectrum band that is available for use by multipleoperators in an equally shared or prioritized manner). The operation(s)at block 2005 may be performed using the wireless communicationmanagement component 1420, 1520, 1620, 1720, 1860, or 1960 describedwith reference to FIG. 14, 15, 16, 17, 18, or 19, or the first RATcommunications sensing component 1435 or 1535 described with referenceto FIG. 14 or 15.

At block 2010, the method 2000 may include configuring, in response tothe sensing performed at block 2005, at least one parameter of a secondRAT (e.g., a cellular RAT) used by a device to contend for access to theshared radio frequency spectrum band. The operation(s) at block 2010 maybe performed using the wireless communication management component 1420,1520, 1620, 1720, 1860, or 1960 described with reference to FIG. 14, 15,16, 17, 18, or 19, or the second RAT parameter configuration component1440 or 1540 described with reference to FIG. 14 or 15.

At block 2015, and as part of (e.g., as an example of), or incombination with, the operation(s) performed at block 2010, the method2000 may optionally include configuring at least one LBT parameter usedby a device (e.g., a parameter of a CCA procedure or ECCA procedure usedby a base station or one or more UEs).

In some examples, the method 2000 may be performed by a base station ora UE. When the method 2000 is performed by a base station, the devicefor which the at least one parameter of the second RAT is configured maybe the base station, a single UE, or a plurality of UEs (e.g., all ofthe UEs of a cell in which the base station operates). When the method2000 is performed by a UE, the device for which the at least oneparameter of the second RAT is configured may be the UE.

Thus, the method 2000 may provide for wireless communication. It shouldbe noted that the method 2000 is just one implementation and that theoperations of the method 2000 may be rearranged or otherwise modifiedsuch that other implementations are possible.

FIG. 21 is a flow chart illustrating an exemplary method 2100 forwireless communication, in accordance with various aspects of thepresent disclosure. For clarity, the method 2100 is described below withreference to aspects of one or more of the base stations 105, 205,205-a, 505, or 1805 described with reference to FIG. 1, 2, 5, or 18,aspects of one or more of the UEs 115, 215, 215-a, 215-b, 215-c, or 1915described with reference to FIG. 1, 2, or 19, or aspects of one or moreof the apparatuses 705, 805, 905, 1005, 1105, 1205, 1305, 1405, 1505,1605, or 1705 described with reference to FIG. 7, 8, 9, 10, 11, 12, 13,14, 15, 16, or 17. In some examples, a base station, UE, or apparatusmay execute one or more sets of codes to control the functional elementsof the base station, UE, or apparatus to perform the functions describedbelow. Additionally or alternatively, the base station, UE, or apparatusmay perform one or more of the functions described below usingspecial-purpose hardware.

At block 2105, the method 2100 may include detecting a number oftransmitters (e.g., a number of Wi-Fi transmitters) within an energydetection range of a device (e.g., within range of a base station, UE,or other apparatus). The operation(s) at block 2105 may be performedusing the wireless communication management component 1420, 1520, 1620,1720, 1860, or 1960 described with reference to FIG. 14, 15, 16, 17, 18,or 19, the first RAT communications sensing component 1435 or 1535described with reference to FIG. 14 or 15, or the transmitter detectioncomponent 1545 described with reference to FIG. 15.

At block 2110, the method 2100 may include determining a failure rate oftransmissions (e.g., subframes) for which feedback is reported (e.g., toa base station or other apparatus). The operation(s) at block 2105 maybe performed using the wireless communication management component 1420,1520, 1620, 1720, 1860, or 1960 described with reference to FIG. 14, 15,16, 17, 18, or 19, the first RAT communications sensing component 1435or 1535 described with reference to FIG. 14 or 15, or the transmissionfailure identification component 1550 described with reference to FIG.15.

At block 2115, the method 2100 may include determining an erasure ratefor transmissions (e.g., subframes) for which an error is not reported(e.g., to a base station or other apparatus, because of burstyinterference blanking ACKs/NAKs). The operation(s) at block 2105 may beperformed using the wireless communication management component 1420,1520, 1620, 1720, 1860, or 1960 described with reference to FIG. 14, 15,16, 17, 18, or 19, the first RAT communications sensing component 1435or 1535 described with reference to FIG. 14 or 15, or the erasure rateidentification component 1555 described with reference to FIG. 15.

At block 2120, the method 2100 may include detecting a variancebetween 1) a supported modulation and coding scheme (e.g., an MCS basedon a determined RSRP) and 2) an MCS actually used (e.g., an MCS based onouter loop HARQ processing). The operation(s) at block 2105 may beperformed using the wireless communication management component 1420,1520, 1620, 1720, 1860, or 1960 described with reference to FIG. 14, 15,16, 17, 18, or 19, the first RAT communications sensing component 1435or 1535 described with reference to FIG. 14 or 15, or the MCS variationdetection component 1560 described with reference to FIG. 15.

At block 2125, the method 2100 may include sensing an indication offirst RAT (e.g., a Wi-Fi RAT) communications occupying a shared radiofrequency spectrum band, based at least in part on one or more of thedetections or determinations made in block 2105, 2110, 2115, or 2120 (oron one or more additional or alternative factors). The shared radiofrequency spectrum band may include a radio frequency spectrum band forwhich transmitting apparatuses may need to contend for access (e.g., aradio frequency spectrum band that is available for unlicensed use, suchas Wi-Fi use, or a radio frequency spectrum band that is available foruse by multiple operators in an equally shared or prioritized manner).The operation(s) at block 2125 may be performed using the wirelesscommunication management component 1420, 1520, 1620, 1720, 1860, or 1960described with reference to FIG. 14, 15, 16, 17, 18, or 19, or the firstRAT communications sensing component 1435 or 1535 described withreference to FIG. 14 or 15.

At block 2130, the method 2100 may include configuring, in response tothe sensing performed at block 2125, at least one parameter of a secondRAT (e.g., a cellular RAT) used by a device to contend for access to theshared radio frequency spectrum band. The operation(s) at block 2130 maybe performed using the wireless communication management component 1420,1520, 1620, 1720, 1860, or 1960 described with reference to FIG. 14, 15,16, 17, 18, or 19, or the second RAT parameter configuration component1440 or 1540 described with reference to FIG. 14 or 15.

Blocks 2135, 2140, 2145, 2150, 2155, and 2160 illustrate variousoptional configuration operations that may be performed as part of(e.g., examples of), or in combination with, the operation(s) performedat block 2130.

At block 2135, the method 2100 may include configuring an ECCA procedurefor a device (e.g., a base station or one or more UEs). In someexamples, the operation(s) at block may include configuring a range ofnumbers from which a random number is selected. The random number maydetermine a number of CCA slots over which a device performs an ECCAprocedure. In some examples, the range of numbers may be configured byat least one of: increasing a lower bound of the range of numbers, orincreasing an upper bound of the range of numbers, or a combinationthereof. In some examples, the operation(s) at block 2135 may also oralternatively include configuring a maximum number of CCA slots overwhich an ECCA procedure is performed. In some examples, the maximumnumber of CCA slots may be configured, for example, by linearlyincreasing the maximum number of CCA slots or linearly decreasing themaximum number of CCA slots. In some examples, the maximum number of CCAslots may be configured by multiplicatively increasing the number of CCAslots or linearly decreasing the number of CCA slots. In some examples,the maximum number of CCA slots may be configured by multiplicativelyincreasing the number of CCA slots or multiplicatively decreasing thenumber of CCA slots. The operation(s) at block 2135 may be performedusing the wireless communication management component 1420, 1520, 1620,1720, 1860, or 1960 described with reference to FIG. 14, 15, 16, 17, 18,or 19, the second RAT parameter configuration component 1440 or 1540described with reference to FIG. 14 or 15, or the ECCA configurationcomponent 1565 or ECCA range configuration component 1595 described withreference to FIG. 15.

At block 2140, the method 2100 may include identifying a number ofconsecutive CCA slots for which the shared radio frequency spectrum bandis available before a device wins contention for access to the sharedradio frequency spectrum band. When a device has not won contention foraccess to the shared radio frequency spectrum band, the identifiednumber of CCA slots may be a last number of CCA slots in which an ECCAprocedure is performed. Alternatively, when the device has not woncontention for access to the shared radio frequency spectrum band, theidentified number of CCA slots may include at least one of: a lastnumber of CCA slots in which an ECCA procedure is performed, or a numberof CCA slots in which the ECCA procedure is performed in combinationwith at least one CCA slot following a last CCA slot in which the ECCAprocedure is performed. When the device has won contention for access tothe shared radio frequency spectrum band and is in an idle state withrespect to the shared radio frequency spectrum band, the specifiednumber of CCA slots may include CCA slots in which CCA procedures are tobe performed. The operation(s) at block 2140 may be performed using thewireless communication management component 1420, 1520, 1620, 1720,1860, or 1960 described with reference to FIG. 14, 15, 16, 17, 18, or19, the second RAT parameter configuration component 1440 or 1540described with reference to FIG. 14 or 15, or the consecutive CCA slotconfiguration component 1570 described with reference to FIG. 15.

At block 2145, the method 2100 may include configuring a CCA energydetection threshold for at least one CCA slot in which at least one CCAprocedure is performed. Also or alternatively, the operation(s)performed at block 2145 may include configuring the device to sense anenergy level of the shared radio frequency spectrum band following aperiod in which the shared radio frequency spectrum band is occupied,and configuring a CCA energy detection threshold based at least in parton the sensed energy. The operation(s) may also include configuring thedevice to perform a number of CCA procedures based at least in part onthe CCA energy detection threshold, in a set of CCA slots, andconfiguring the device to win contention for access to the shared radiofrequency spectrum band when the shared radio frequency spectrum band isdetermined to be available for a subset of CCA slots included in the setof CCA slots (e.g., a subset including one, a plurality of, or all ofthe CCA slots in the set of CCA slots). In some examples, the secondnumber of CCA slots may be a number of consecutive CCA slots. Theoperation(s) at block 2145 may be performed using the wirelesscommunication management component 1420, 1520, 1620, 1720, 1860, or 1960described with reference to FIG. 14, 15, 16, 17, 18, or 19, the secondRAT parameter configuration component 1440 or 1540 described withreference to FIG. 14 or 15, or the CCA energy detection thresholdconfiguration component 1575 described with reference to FIG. 15.

At block 2150, the method 2100 may include increasing a duration of alast CCA slot in which an ECCA procedure is performed. In some examples,the operation(s) at block 2150 may also include configuring a CCA energydetection threshold for the last CCA slot. The operation(s) at block2150 may be performed using the wireless communication managementcomponent 1420, 1520, 1620, 1720, 1860, or 1960 described with referenceto FIG. 14, 15, 16, 17, 18, or 19, the second RAT parameterconfiguration component 1440 or 1540 described with reference to FIG. 14or 15, or the CCA slot duration configuration component 1580 describedwith reference to FIG. 15.

At block 2155, the method 2100 may include configuring the device toperform a plurality of ECCA procedures to contend for access to theshared radio frequency spectrum band. In some examples, the plurality ofECCA procedures may include a first ECCA procedure followed by a secondECCA procedure. In some examples, the first ECCA procedure may beconfigured to be performed over a first number of CCA slots and thesecond ECCA procedure may be configured to be performed over a secondnumber of CCA slots. The second number may be less than the firstnumber. In some examples, the operation(s) at block 2155 may alsoinclude configuring the device to identify a number of consecutive CCAslots for which the shared radio frequency spectrum band is available,during or after the second ECCA, before the device wins contention foraccess to the shared radio frequency spectrum band. The operation(s) atblock 2155 may be performed using the wireless communication managementcomponent 1420, 1520, 1620, 1720, 1860, or 1960 described with referenceto FIG. 14, 15, 16, 17, 18, or 19, the second RAT parameterconfiguration component 1440 or 1540 described with reference to FIG. 14or 15, or the ECCA number configuration component 1585 described withreference to FIG. 15.

At block 2160, the method 2100 may include configuring a defermentperiod for a device. The deferment period may cause the device to waitfor the deferment period, upon determining the shared radio frequencyspectrum band is unavailable, before performing an additional number ofCCA procedures (which in some cases may include a number of ECCAprocedures). The operation(s) at block 2160 may be performed using thewireless communication management component 1420, 1520, 1620, 1720,1860, or 1960 described with reference to FIG. 14, 15, 16, 17, 18, or19, the second RAT parameter configuration component 1440 or 1540described with reference to FIG. 14 or 15, or the CCA/ECCA defermentperiod configuration component 1590 described with reference to FIG. 15.

In some examples, the method 2100 may be performed by a base station ora UE. When the method 2100 is performed by a base station, the devicefor which the at least one parameter of the second RAT is configured maybe the base station, a single UE, or a plurality of UEs (e.g., all ofthe UEs of a cell in which the base station operates). When the method2100 is performed by a UE, the device for which the at least oneparameter of the second RAT is configured may be the UE.

Thus, the method 2100 may provide for wireless communication. It shouldbe noted that the method 2100 is just one implementation and that theoperations of the method 2100 may be rearranged or otherwise modifiedsuch that other implementations are possible.

In some examples, aspects of the methods 2000 and 2100 described withreference to FIGS. 20 and 21 may be combined.

FIG. 22 is a flow chart illustrating an exemplary method 2200 forwireless communication, in accordance with various aspects of thepresent disclosure. For clarity, the method 2200 is described below withreference to aspects of one or more of the base stations 105, 205,205-a, 505, or 1805 described with reference to FIG. 1, 2, 5, or 18,aspects of one or more of the UEs 115, 215, 215-a, 215-b, 215-c, or 1915described with reference to FIG. 1, 2, or 19, or aspects of one or moreof the apparatuses 705, 805, 905, 1005, 1105, 1205, 1305, 1405, 1505,1605, or 1705 described with reference to FIG. 7, 8, 9, 10, 11, 12, 13,14, 15, 16, or 17. In some examples, a base station, UE, or apparatusmay execute one or more sets of codes to control the functional elementsof the base station, UE, or apparatus to perform the functions describedbelow. Additionally or alternatively, the base station, UE, or apparatusmay perform one or more of the functions described below usingspecial-purpose hardware.

In some examples, the method 2200 may include configuring an ECCAprocedure. For examples, at block 2205, the method 2200 may includerandomly selecting a number from a range of numbers extending between alower bound and an upper bound. The number may determine how many CCAslots a shared radio frequency spectrum band must be determined“available,” during the performance of an ECCA procedure, before anapparatus performing the ECCA procedure can win contention for access tothe shared radio frequency spectrum band. The shared radio frequencyspectrum band may include a radio frequency spectrum band for whichtransmitting apparatuses may need to contend for access (e.g., a radiofrequency spectrum band that is available for unlicensed use, such asWi-Fi use, or a radio frequency spectrum band that is available for useby multiple operators in an equally shared or prioritized manner). Theoperation(s) at block 2205 may be performed using the wirelesscommunication management component 1420, 1520, 1620, 1720, 1860, or 1960described with reference to FIG. 14, 15, 16, 17, 18, or 19, or the ECCAprocedure configuration component 1635 or 1735 described with referenceto FIG. 16 or 17.

At block 2210, the method 2200 may include contending for access to ashared radio frequency spectrum band by performing an ECCA procedureover a plurality of CCA slots. The plurality of CCA slots may include afirst number of CCA slots equal to the upper bound. The operation(s) atblock 2210 may be performed using the wireless communication managementcomponent 1420, 1520, 1620, 1720, 1860, or 1960 described with referenceto FIG. 14, 15, 16, 17, 18, or 19, or the ECCA procedure performancecomponent 1640 or 1740 described with reference to FIG. 16 or 17.

At block 2215, the method 2200 may include winning contention for accessto the shared radio frequency spectrum band after determining, whileperforming the ECCA procedure, that the shared radio frequency spectrumband is available for a second number of CCA slots equal to the randomlyselected number. The operation(s) at block 2215 may be performed usingthe wireless communication management component 1420, 1520, 1620, 1720,1860, or 1960 described with reference to FIG. 14, 15, 16, 17, 18, or19, or the ECCA procedure performance component 1640 or 1740 describedwith reference to FIG. 16 or 17.

At block 2220, the method 2200 may optionally include discontinuing theextended CCA procedure upon winning contention for access to the sharedradio frequency spectrum band. The operation(s) at block 2215 may beperformed using the wireless communication management component 1420,1520, 1620, 1720, 1860, or 1960 described with reference to FIG. 14, 15,16, 17, 18, or 19, or the ECCA procedure performance component 1640 or1740 or successful ECCA discontinuation component 1645 or 1745 describedwith reference to FIG. 16 or 17.

In some examples, each of the CCA slots over which the ECCA procedure isperformed may include a preconfigured period of time for which theshared radio frequency spectrum band is available, or an entirety of acontiguous period for which the shared radio frequency spectrum band isunavailable. In other examples, each of the CCA slots over which theECCA procedure is performed may include a preconfigured period of time.

Thus, the method 2200 may provide for wireless communication. It shouldbe noted that the method 2200 is just one implementation and that theoperations of the method 2200 may be rearranged or otherwise modifiedsuch that other implementations are possible.

FIG. 23 is a flow chart illustrating an exemplary method 2300 forwireless communication, in accordance with various aspects of thepresent disclosure. For clarity, the method 2300 is described below withreference to aspects of one or more of the base stations 105, 205,205-a, 505, or 1805 described with reference to FIG. 1, 2, 5, or 18,aspects of one or more of the UEs 115, 215, 215-a, 215-b, 215-c, or 1915described with reference to FIG. 1, 2, or 19, or aspects of one or moreof the apparatuses 705, 805, 905, 1005, 1105, 1205, 1305, 1405, 1505,1605, or 1705 described with reference to FIG. 7, 8, 9, 10, 11, 12, 13,14, 15, 16, or 17. In some examples, a base station, UE, or apparatusmay execute one or more sets of codes to control the functional elementsof the base station, UE, or apparatus to perform the functions describedbelow. Additionally or alternatively, the base station, UE, or apparatusmay perform one or more of the functions described below usingspecial-purpose hardware.

In some examples, the method 2300 may include configuring an ECCAprocedure. For examples, at block 2305, the method 2300 may includerandomly selecting a number from a range of numbers extending between alower bound and an upper bound. The number may determine how many CCAslots a shared radio frequency spectrum band must be determined“available,” during the performance of an ECCA procedure, before anapparatus performing the ECCA procedure can win contention for access tothe shared radio frequency spectrum band. The shared radio frequencyspectrum band may include a radio frequency spectrum band for whichtransmitting apparatuses may need to contend for access (e.g., a radiofrequency spectrum band that is available for unlicensed use, such asWi-Fi use, or a radio frequency spectrum band that is available for useby multiple operators in an equally shared or prioritized manner). Theoperation(s) at block 2305 may be performed using the wirelesscommunication management component 1420, 1520, 1620, 1720, 1860, or 1960described with reference to FIG. 14, 15, 16, 17, 18, or 19, or the ECCAprocedure configuration component 1635 or 1735 described with referenceto FIG. 16 or 17.

At block 2310, the method 2300 may include contending for access to ashared radio frequency spectrum band by performing an ECCA procedureover a first CCA slot or a next CCA slot of a plurality of CCA slots.The plurality of CCA slots may include a first number of CCA slots equalto the upper bound. The operation(s) at block 2310 may be performedusing the wireless communication management component 1420, 1520, 1620,1720, 1860, or 1960 described with reference to FIG. 14, 15, 16, 17, 18,or 19, or the ECCA procedure performance component 1640 or 1740described with reference to FIG. 16 or 17.

At block 2315, and while performing the ECCA procedure, the method 2300may include determining whether the shared radio frequency spectrum bandis available for a second number of CCA slots equal to the randomlyselected number. When the shared radio frequency spectrum band isavailable for the second number of CCA slots, the method 2300 maycontinue at block 2320. When the shared radio frequency spectrum band isnot available for the second number of CCA slots, the method 2300 maycontinue at block 2325. The operation(s) at block 2315 may be performedusing the wireless communication management component 1420, 1520, 1620,1720, 1860, or 1960 described with reference to FIG. 14, 15, 16, 17, 18,or 19, or the ECCA procedure performance component 1640 or 1740described with reference to FIG. 16 or 17.

At block 2320, the method 2300 may include discontinuing the ECCAprocedure and winning contention for access to the shared radiofrequency spectrum. The operation(s) at block 2320 may be performedusing the wireless communication management component 1420, 1520, 1620,1720, 1860, or 1960 described with reference to FIG. 14, 15, 16, 17, 18,or 19, or the ECCA procedure performance component 1640 or 1740 orsuccessful ECCA discontinuation component 1645 or 1745 described withreference to FIG. 16 or 17.

At block 2325, and while performing the ECCA procedure, the method 2300may include determining whether the shared radio frequency spectrum bandis unavailable for a third number of CCA slots equal to the first numberof CCA slots, less the randomly selected number, plus one. When theshared radio frequency spectrum band is unavailable for the third numberof CCA slots, the method 2300 may continue at block 2330. When theshared radio frequency spectrum band is not unavailable for the thirdnumber of CCA slots, the method 2300 may continue at block 2335. Theoperation(s) at block 2325 may be performed using the wirelesscommunication management component 1420, 1520, 1620, 1720, 1860, or 1960described with reference to FIG. 14, 15, 16, 17, 18, or 19, or the ECCAprocedure performance component 1640 or 1740 described with reference toFIG. 16 or 17.

At block 2330, the method 2300 may include discontinuing the ECCAprocedure and failing to win contention for access to the shared radiofrequency spectrum. The operation(s) at block 2330 may be performedusing the wireless communication management component 1420, 1520, 1620,1720, 1860, or 1960 described with reference to FIG. 14, 15, 16, 17, 18,or 19, the ECCA procedure performance component 1640 or 1740 describedwith reference to FIG. 16 or 17, or the unsuccessful ECCAdiscontinuation component 1750 described with reference to FIG. 17.

At block 2335, the method 2300 may include determining whether the ECCAprocedure has been performed over each of the plurality of slots. Whenthe ECCA procedure has been performed over each of the plurality ofslots, the method 2300 may continue at block 2330. When the ECCAprocedure has not been performed over each of the plurality of slots,the method 2300 may continue at block 2310. The operation(s) at block2335 may be performed using the wireless communication managementcomponent 1420, 1520, 1620, 1720, 1860, or 1960 described with referenceto FIG. 14, 15, 16, 17, 18, or 19, or the ECCA procedure performancecomponent 1640 or 1740 described with reference to FIG. 16 or 17.

In some examples, each of the CCA slots over which the ECCA procedure isperformed may include a preconfigured period of time for which theshared radio frequency spectrum band is available, or an entirety of acontiguous period for which the shared radio frequency spectrum band isunavailable. In other examples, each of the CCA slots over which theECCA procedure is performed may include a preconfigured period of time.

Thus, the method 2300 may provide for wireless communication. It shouldbe noted that the method 2300 is just one implementation and that theoperations of the method 2300 may be rearranged or otherwise modifiedsuch that other implementations are possible.

In some examples, aspects of the methods 2200 and 2300 described withreference to FIGS. 22 and 23 may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, andother systems. The terms “system” and “network” are often usedinterchangeably. A CDMA system may implement a radio technology such asCDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and Aare commonly referred to as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) iscommonly referred to as CDMA2000 1×EV-DO, High Rate Packet Data (HRPD),etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. ATDMA system may implement a radio technology such as Global System forMobile Communications (GSM). An OFDMA system may implement a radiotechnology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA),IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM™, etc.UTRA and E-UTRA are part of Universal Mobile Telecommunication System(UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are newreleases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, andGSM are described in documents from an organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned above as well as other systemsand radio technologies, including cellular (e.g., LTE) communicationsover a shared radio frequency spectrum band. The description above,however, describes an LTE/LTE-A system for purposes of example, and LTEterminology is used in much of the description above, although thetechniques are applicable beyond LTE/LTE-A applications.

The detailed description set forth above in connection with the appendeddrawings describes examples and does not represent all of the examplesthat may be implemented or that are within the scope of the claims. Theterms “example” and “exemplary,” when used in this description, mean“serving as an example, instance, or illustration,” and not “preferred”or “advantageous over other examples.” The detailed description includesspecific details for the purpose of providing an understanding of thedescribed techniques. These techniques, however, may be practicedwithout these specific details. In some instances, well-known structuresand apparatuses are shown in block diagram form in order to avoidobscuring the concepts of the described examples.

Information and signals may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the above description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connectionwith the disclosure herein may be implemented or performed with ageneral-purpose processor, a digital signal processor (DSP), an ASIC, anFPGA or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, or any combination thereof designedto perform the functions described herein. A general-purpose processormay be a microprocessor, but in the alternative, the processor may beany conventional processor, controller, microcontroller, or statemachine. A processor may also be implemented as a combination ofcomputing devices, e.g., a combination of a DSP and a microprocessor,multiple microprocessors, one or more microprocessors in conjunctionwith a DSP core, or any other such configuration.

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope and spirit of the disclosure and appended claims. For example,due to the nature of software, functions described above can beimplemented using software executed by a processor, hardware, firmware,hardwiring, or combinations of any of these. Features implementingfunctions may also be physically located at various positions, includingbeing distributed such that portions of functions are implemented atdifferent physical locations. As used herein, including in the claims,the term “or,” when used in a list of two or more items, means that anyone of the listed items can be employed by itself, or any combination oftwo or more of the listed items can be employed. For example, if acomposition is described as containing components A, B, or C, thecomposition can contain A alone; B alone; C alone; A and B incombination; A and C in combination; B and C in combination; or A, B,and C in combination. Also, as used herein, including in the claims,“or” as used in a list of items (for example, a list of items prefacedby a phrase such as “at least one of” or “one or more of”) indicates adisjunctive list such that, for example, a list of “at least one of A,B, or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B andC).

Computer-readable media includes both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage medium may be anyavailable medium that can be accessed by a general purpose or specialpurpose computer. By way of example, and not limitation,computer-readable media can include RAM, ROM, EEPROM, flash memory,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, include compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above are also includedwithin the scope of computer-readable media.

The previous description of the disclosure is provided to enable aperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the scope of thedisclosure. Thus, the disclosure is not to be limited to the examplesand designs described herein but is to be accorded the broadest scopeconsistent with the principles and novel features disclosed herein.

What is claimed is:
 1. A method for wireless communication, comprising:randomly selecting a number from a range of numbers extending between alower bound and an upper bound; contending for access to a shared radiofrequency spectrum band by performing an extended clear channelassessment (CCA) procedure over a plurality of CCA slots, the pluralityof CCA slots comprising a first number of CCA slots equal to the upperbound; and winning contention for access to the shared radio frequencyspectrum band after determining, while performing the extended CCAprocedure, that the shared radio frequency spectrum band is availablefor a second number of CCA slots equal to the randomly selected number.2. The method of claim 1, further comprising: discontinuing the extendedCCA procedure and failing to win contention for access to the sharedradio frequency spectrum band after determining, while performing theextended CCA procedure, that the shared radio frequency spectrum band isunavailable for a third number of CCA slots equal to the first number ofCCA slots, less the randomly selected number, plus one.
 3. The method ofclaim 2, wherein the extended CCA procedure is discontinued at a sameCCA slot that the shared radio frequency spectrum band is determined tobe unavailable.
 4. The method of claim 2, further comprising:contending, based at least in part on discontinuing the extended CCAprocedure, for access to the shared radio frequency spectrum band byperforming a second extended CCA procedure over a fourth plurality ofCCA slots, the second extended CCA procedure following the CCAprocedure.
 5. The method of claim 4, wherein performing the secondextended CCA procedure comprises: beginning the second extended CCAprocedure immediately after the extended CCA procedure is discontinued.6. The method of claim 4, wherein performing the second extended CCAprocedure comprises: beginning the second extended CCA procedurefollowing a deferment period, the determent period following theextended CCA procedure.
 7. The method of claim 4, wherein performing thesecond extended CCA procedure comprises: beginning the second extendedCCA procedure at a next occasion for contending for access to the sharedradio frequency spectrum band, the next occasion beginning after theextended CCA procedure is discontinued.
 8. The method of claim 4,further comprising: configuring a second range of numbers from which asecond number is randomly selected, wherein the second randomly selectednumber determines a second number of CCA slots over which the deviceperforms the second extended CCA procedure, and wherein the second rangeof numbers extends between a lower bound and an upper bound.
 9. Themethod of claim 8, wherein configuring the second range of numberscomprises: doubling the upper bound of the second range of numbers basedat least in part on discontinuing the extended CCA procedure.
 10. Themethod of claim 8, wherein configuring the second range of numberscomprises: linearly increasing the upper bound of the second range ofnumbers, multiplicatively increasing the upper bound of the second rangeof numbers, or a combination thereof, based at least in part ondiscontinuing the extended CCA procedure.
 11. The method of claim 8,further comprising: winning contention for access to the shared radiofrequency spectrum band after determining, during the second extendedCCA procedure, that the shared radio frequency spectrum band isavailable for a second number of CCA slots equal to the second randomlyselected number; and decreasing, based at least in part on winningcontention during the second extended CCA procedure, an upper bound of athird range of numbers for one or more subsequent extended CCAprocedures.
 12. The method of claim 1, further comprising: discontinuingthe extended CCA procedure based at least in part on winning contentionfor access to the shared radio frequency spectrum band.
 13. The methodof claim 1, further comprising: transmitting a channel reservationsignal to reserve the shared radio frequency spectrum band based atleast in part on winning contention for access to the shared radiofrequency spectrum band.
 14. The method of claim 13, wherein the channelreservation signal is transmitted at a same CCA slot that the sharedradio frequency spectrum band is determined to be available.
 15. Anapparatus for wireless communication, comprising: a processor, memorycoupled with the processor; and instructions stored in the memory andexecutable by the processor to cause the apparatus to: randomly select anumber from a range of numbers extending between a lower bound and anupper bound; contend for access to a shared radio frequency spectrumband by performing an extended clear channel assessment (CCA) procedureover a plurality of CCA slots, the plurality of CCA slots comprising afirst number of CCA slots equal to the upper bound; and win contentionfor access to the shared radio frequency spectrum band afterdetermining, while performing the extended CCA procedure, that theshared radio frequency spectrum band is available for a second number ofCCA slots equal to the randomly selected number.
 16. The apparatus ofclaim 15, wherein the instructions are further executable by theprocessor to cause the apparatus to: discontinue the extended CCAprocedure and fail to win contention for access to the shared radiofrequency spectrum band after determining, while performing the extendedCCA procedure, that the shared radio frequency spectrum band isunavailable for a third number of CCA slots equal to the first number ofCCA slots, less the randomly selected number, plus one.
 17. Theapparatus of claim 16, wherein the extended CCA procedure isdiscontinued at a same CCA slot that the shared radio frequency spectrumband is determined to be unavailable.
 18. The apparatus of claim 16,wherein the instructions are further executable by the processor tocause the apparatus to: contend, based at least in part on discontinuingthe extended CCA procedure, for access to the shared radio frequencyspectrum band by performing a second extended CCA procedure over afourth plurality of CCA slots, the second extended CCA procedurefollowing the CCA procedure.
 19. The apparatus of claim 18, wherein theinstructions to perform the second extended CCA procedure are executableby the processor to cause the apparatus to: begin the second extendedCCA procedure immediately after the extended CCA procedure isdiscontinued.
 20. The apparatus of claim 18, wherein the instructions toperform the second extended CCA procedure are executable by theprocessor to cause the apparatus to: begin the second extended CCAprocedure following a deferment period, the determent period followingthe extended CCA procedure.
 21. The apparatus of claim 18, wherein theinstructions to perform the second extended CCA procedure are executableby the processor to cause the apparatus to: begin the second extendedCCA procedure at a next occasion for contending for access to the sharedradio frequency spectrum band, the next occasion beginning after theextended CCA procedure is discontinued.
 22. The apparatus of claim 18,wherein the instructions are further executable by the processor tocause the apparatus to: configure a second range of numbers from which asecond number is randomly selected, wherein the second randomly selectednumber determines a second number of CCA slots over which the deviceperforms the second extended CCA procedure, and wherein the second rangeof numbers extends between a lower bound and an upper bound.
 23. Theapparatus of claim 22, wherein the instructions to perform the secondextended CCA procedure are executable by the processor to cause theapparatus to: double the upper bound of the second range of numbersbased at least in part on discontinuing the extended CCA procedure. 24.The apparatus of claim 22, wherein the instructions to perform thesecond extended CCA procedure are executable by the processor to causethe apparatus to: linearly increase the upper bound of the second rangeof numbers, multiplicatively increase the upper bound of the secondrange of numbers, or a combination thereof, based at least in part ondiscontinuing the extended CCA procedure.
 25. The apparatus of claim 22,wherein the instructions are further executable by the processor tocause the apparatus to: win contention for access to the shared radiofrequency spectrum band after determining, during the second extendedCCA procedure, that the shared radio frequency spectrum band isavailable for a second number of CCA slots equal to the second randomlyselected number; and decrease, based at least in part on winningcontention during the second extended CCA procedure, an upper bound of athird range of numbers for one or more subsequent extended CCAprocedures.
 26. The apparatus of claim 15, wherein the instructions arefurther executable by the processor to cause the apparatus to:discontinue the extended CCA procedure based at least in part on winningcontention for access to the shared radio frequency spectrum band. 27.The apparatus of claim 15, wherein the instructions are furtherexecutable by the processor to cause the apparatus to: transmit achannel reservation signal to reserve the shared radio frequencyspectrum band based at least in part on winning contention for access tothe shared radio frequency spectrum band.
 28. The apparatus of claim 27,wherein the channel reservation signal is transmitted at a same CCA slotthat the shared radio frequency spectrum band is determined to beavailable.
 29. An apparatus for wireless communication, comprising:means for randomly selecting a number from a range of numbers extendingbetween a lower bound and an upper bound; means for contending foraccess to a shared radio frequency spectrum band by performing anextended clear channel assessment (CCA) procedure over a plurality ofCCA slots, the plurality of CCA slots comprising a first number of CCAslots equal to the upper bound; and means for winning contention foraccess to the shared radio frequency spectrum band after determining,while performing the extended CCA procedure, that the shared radiofrequency spectrum band is available for a second number of CCA slotsequal to the randomly selected number.
 30. A non-transitorycomputer-readable medium storing code for wireless communication, thecode comprising instructions executable by a processor to: randomlyselect a number from a range of numbers extending between a lower boundand an upper bound; contend for access to a shared radio frequencyspectrum band by performing an extended clear channel assessment (CCA)procedure over a plurality of CCA slots, the plurality of CCA slotscomprising a first number of CCA slots equal to the upper bound; and wincontention for access to the shared radio frequency spectrum band afterdetermining, while performing the extended CCA procedure, that theshared radio frequency spectrum band is available for a second number ofCCA slots equal to the randomly selected number.